All tools

Tools every web developer needs.

• JSON Formatter
  Pretty-print, minify, and validate JSON. Detects syntax errors with line numbers and supports nested structures of any depth.
• JSON Diff
  Compare two JSON values semantically. Ignores key order; shows added, removed, and changed fields with their JSONPath — great for diffing API responses and config files.
• JSON to XML Converter
  Convert JSON objects and arrays to well-formed XML. Maps object keys to elements, array items to repeated elements, with optional root wrapper.
• JSON to YAML Converter
  Convert JSON to clean indented YAML for Kubernetes manifests, Docker Compose, CI configs, and Helm charts. Preserves nested structures.
• JSON to CSV Converter
  Convert JSON arrays to CSV with automatic header detection from object keys. Handles nested values and arbitrary delimiters.
• JSON to TypeScript
  Generate TypeScript interfaces and types from any sample JSON. Handles nested objects, arrays, optional fields, and mixed types. Paste JSON, copy the interface.
• YAML Formatter
  Format and validate YAML for config files, Kubernetes manifests, Docker Compose, and CI pipelines. Normalizes indentation and surfaces syntax errors.
• YAML to JSON Converter
  Convert YAML to JSON for APIs, config files, and pipelines. Supports indented mappings, sequences, scalars, and nested objects.
• YAML to XML Converter
  Convert YAML to well-formed XML for legacy integrations. Preserves nested mappings and sequences as nested elements with text values.
• YAML to CSV Converter
  Convert YAML arrays of records to CSV. Flattens nested objects with dot-notation column names so spreadsheet tools can read structured YAML data.
• XML Formatter
  Format, indent, and validate XML documents. Detects malformed tags, unclosed elements, and bad attributes with clear line-level error messages. Great for config and API work.
• XML to JSON Converter
  Convert XML to JSON for legacy API integration, SOAP responses, and config migration. Handles attributes, namespaces, and text content.
• XML to YAML Converter
  Convert XML documents to clean indented YAML. Handles attributes, repeated elements, and text content; great for migrating legacy configs.
• XML to CSV Converter
  Flatten repeated XML elements into CSV rows with attributes and child text as columns. Great for opening XML data in Excel or Sheets.
• CSV to JSON Converter
  Convert CSV to a JSON array of objects. Uses the first row as keys, handles quoted values, and detects common delimiters automatically.
• CSV to XML Converter
  Convert CSV rows into XML elements with column headers as tag names. Useful for Excel exports, legacy systems, and ETL pipelines.
• CSV to YAML Converter
  Convert CSV to YAML for use in config files, Ansible playbooks, and Kubernetes ConfigMaps. Uses the header row as YAML keys.
• Token Counter for GPT, Claude, Llama
  Count tokens for ChatGPT, GPT-4o, Claude, Llama, and Gemini before hitting context limits. Shows per-model token count, character count, and approximate API cost.
• LLM JSON Schema Validator
  Validate JSON Schemas for OpenAI strict mode, function calling, Anthropic tool use, and Gemini controlled generation. Catch vendor-specific schema errors before shipping.
• JWT Decoder
  Decode JSON Web Tokens and inspect the header, payload, and signature. Paste any JWT to see claims, expiry, issuer, and algorithm — no secret key needed to decode.
• JWT Generator
  Sign JSON Web Tokens with HS256, HS384, or HS512. Set custom claims, expiry, and issuer — then copy the signed token for use in API testing or auth flows.
• Regex Tester
  Test JavaScript regular expressions live with instant match highlighting. Supports all JS regex flags (g, i, m, s, u) and shows match groups, indices, and global matches.
• SQL Formatter
  Pretty-print and format SQL for any major dialect — MySQL, PostgreSQL, SQLite, T-SQL, and more. Normalizes indentation, keywords, and spacing for readable, consistent queries.
• URL Encoder/Decoder
  Percent-encode and decode URLs and query string values. Handles full URLs or individual components — paste any URL to encode special characters or decode percent-encoded strings.
• URL Parser
  Decompose any URL into its components — protocol, host, port, path, query parameters, and fragment. Great for debugging redirect chains, API endpoints, and UTM parameters.
• Curl to Code Converter
  Paste a curl command, get equivalent code in JavaScript (fetch/axios), Python (requests), or Go (net/http). Handles headers, JSON bodies, basic auth, and form data.
• HTTP Status Code Reference
  Searchable reference for every HTTP status code with plain-English summaries and the gotchas devs actually hit: 301 vs 308, 401 vs 403, 404 vs 410, 400 vs 422.
• Base64 Encoder/Decoder
  Encode text or binary data to Base64 and decode Base64 strings back to text. Supports standard and URL-safe Base64. Useful for data URIs, API tokens, and email attachments.
• Image to Base64
  Convert any image file into a Base64 data URI for embedding directly in CSS or HTML. Supports PNG, JPG, GIF, WebP, and SVG. No upload — processed entirely in your browser.
• String Escape/Unescape
  Escape and unescape strings for JSON, JavaScript, HTML, and SQL. Handles special characters, backslashes, quotes, newlines, and Unicode escape sequences instantly.
• HTML Entities Encoder
  Encode text to HTML entities and decode entities back to text. Converts angle brackets, ampersands, quotes, and other special characters to safe equivalents for use in HTML templates and CMS workflows.
• HTML Editor
  Write HTML with live preview side-by-side. Syntax-highlighted editor with formatted source view — useful for testing snippets, email templates, or quick mockups in your browser.
• Markdown Preview
  Live markdown editor with GitHub-flavored rendering. Supports tables, code blocks, task lists, and strikethrough. Great for drafting README files or documentation.
• Color Picker
  Pick any color visually and copy the value in HEX, RGB, HSL, or OKLCH. Enter a hex code to convert to other formats. Includes a color wheel, shade slider, and clipboard copy.
• CSS Minifier
  Minify CSS for production by stripping whitespace, comments, and redundant rules. Paste your stylesheet and get the compressed output ready to ship or inline.
• JS Minifier
  Minify JavaScript using Terser — removes whitespace, shortens variable names, and removes dead code. Paste your JS and get a production-ready compressed bundle.
• Cron Expression Parser — Explain & Preview Runs
  Explain any cron expression in plain English and preview the next run times. Supports 5-field crontab, 6-field, and @hourly/@daily/@weekly shortcuts. Free, no signup.
• .gitignore Generator
  Build a .gitignore file from community templates for any language or framework — Node, Python, Go, Java, React, Rails, and more. Select multiple templates and merge them in one click.
• .htaccess Generator
  Generate common Apache .htaccess snippets — redirects, URL rewrites, HTTPS enforcement, custom error pages, CORS headers, and caching rules. Copy the snippet you need.

Manipulate, count, compare, and clean text.

• Text Diff
  Side-by-side diff comparison of two text blocks with line-by-line highlighting. Shows added, removed, and changed lines — useful for comparing document versions or config files.
• Remove Duplicate Lines
  Remove duplicate lines from any list or text block while preserving original order. Optionally trim whitespace and ignore case before deduplication. Results update instantly.
• Sort Lines / Sort List Online
  Sort a list of words, names, or numbers — alphabetically A→Z or Z→A, numerically, or randomly. Paste any list and get sorted results instantly.
• Word & Text Counter
  Count words, characters, lines, sentences, and reading time instantly. Paste any text — article, essay, or code — and get a live breakdown. Also shows unique word count and average word length.
• Case Converter
  Convert text between UPPERCASE, lowercase, Title Case, Sentence case, camelCase, PascalCase, snake_case, and kebab-case. Paste any text and switch case in one click.
• Text Reverser
  Reverse the characters, words, or individual lines of any text. Useful for debugging palindromes, creating mirror text, or just having fun with strings.
• Find & Replace
  Bulk find and replace across any block of text with plain text or regex patterns. Supports case-sensitive matching, global replace, and regular expression capture groups.
• Text to URL Slug
  Convert any title or string into a clean, hyphenated URL slug. Strips accents, punctuation, and spaces. Useful for generating SEO-friendly URLs and blog post paths.
• Lorem Ipsum Generator
  Generate paragraphs, sentences, or words of classic lorem ipsum placeholder text. Choose the amount and copy instantly — useful for mockups, wireframes, and design prototypes.
• Morse Code Translator
  Translate text to Morse code and Morse code back to text, with audio playback of the dots and dashes. Supports the full International Morse Code alphabet and numbers.

Set operations, filtering, and clipboard transforms for lists.

• List Stats
  Get statistics on any list: total count, unique count, min and max line length, average length, and the longest and shortest items. Useful for auditing data before further processing.
• List Set Operations
  Perform set operations on two lists: union, intersection, difference, A-only, B-only, and symmetric difference. Paste two lists and choose the operation — results update instantly.
• List Filter
  Keep or remove lines matching a plain-text substring or regular expression. Useful for filtering log output, cleaning data, or extracting matching lines from large lists.
• Comma to Lines Converter
  Convert between comma-separated values and one-item-per-line format. Handles quoted fields, trims whitespace, and removes duplicates. Paste CSV data, get a clean list — and back.
• List to JSON Array
  Convert a one-item-per-line list into a JSON array of strings and back again. Handles quoting and escaping automatically — useful for turning clipboard lists into API payloads.
• Column Picker
  Extract a specific column from tab-separated or comma-separated rows. Enter column index or name — useful for pulling a single field from TSV exports or pasted spreadsheet data.
• Prefix / Suffix Wrapper
  Wrap every line with a custom prefix and suffix. Useful for building SQL IN clauses ('value'), quoting shell arguments, wrapping HTML tags, or generating code from a list.
• Number Sequence Generator
  Expand range patterns like 1..100 or 0,2,4..20 into complete numeric lists. Supports step size, comma-separated output, and custom separators — great for test data and scripting.

Date math, age, and timezone tools.

• Days Between Dates — How Many Days Calculator
  Find how many days are between two dates — plus weeks, months, and years. Counts calendar days inclusive or exclusive. Free, runs in your browser, no signup.
• Time Zone Converter — Convert Time Across Zones
  Convert any time across 10+ world time zones instantly. DST-aware — New York, London, Tokyo, Kolkata, Sydney & more. Runs locally in your browser, no signup.
• Unix Timestamp Converter
  Convert Unix epoch timestamps to human-readable dates and vice versa. Supports seconds and milliseconds. Instantly shows UTC and local time — no signup needed.
• Date Calculator
  Add or subtract days, weeks, months, or years from any date to find a future or past date. Handles leap years correctly — useful for deadlines, scheduling, and date math.
• Week Number
  Find the ISO 8601 week number for any date and see which dates fall in that week. Useful for project planning, payroll periods, and international reporting standards.
• Countdown Timer
  Live countdown to any future date or event — shows days, hours, minutes, and seconds remaining. Set a target date and share the link or bookmark it for quick access.
• Stopwatch
  Online stopwatch with lap tracking. Start, pause, and record lap splits — all in your browser. No install needed. Accurate to milliseconds for timing tasks, workouts, or experiments.
• Age Calculator
  Calculate your exact age in years, months, and days from your date of birth. Also shows the next birthday countdown and total days, hours, and minutes lived.

Calculators for everyday and advanced math.

• Percentage Calculator
  Calculate what percent of a number is, find percent change, and reverse-calculate any percentage. Three modes — pick the one that matches your problem, get the answer instantly.
• Average Calculator
  Calculate mean, median, mode, range, sum, min, and max for any list of numbers. Paste in grades, scores, or measurements — results update instantly.
• Fraction Calculator
  Add, subtract, multiply, and divide fractions with full step-by-step results showing the LCD, equivalent fractions, and simplified answer. Handles mixed numbers and improper fractions.
• Ratio Calculator
  Simplify ratios to lowest terms, convert a ratio to a decimal, scale to any value, and compare two ratios. For recipes, map scales, and aspect ratios.
• Rounding Calculator
  Round numbers to the nearest integer, decimal place, or significant figure. Choose round half-up, half-down, or toward zero. Handles large and small numbers precisely.
• Root Calculator
  Calculate square roots, cube roots, and any nth root with high precision. Handles perfect squares and irrational results — shows the decimal approximation and the radical form.
• Exponent Calculator
  Raise any base to any power — including negative bases, decimal exponents, and fractional powers. Shows the full numeric result with high precision for scientific and engineering work.
• Logarithm Calculator
  Calculate log base 10, natural log (ln), log base 2, and log to any custom base. Shows step-by-step working — useful for chemistry, information theory, and general math.
• Antilog Calculator
  Calculate the antilog (inverse logarithm) for any base — base 10, base e (natural), or a custom base. Converts log values back to their original numbers instantly.
• GCF / GCD Calculator
  Find the greatest common factor (GCF) — also called GCD — of two or more integers. Uses the Euclidean algorithm and shows step-by-step working. Useful for simplifying fractions.
• LCM Calculator
  Find the least common multiple of any set of integers. Shows prime factorization and step-by-step working — useful for adding fractions, scheduling problems, and number theory.
• Factorial Calculator
  Calculate n! for any integer using big-int math that handles very large numbers precisely. Shows the full expanded result — useful for combinatorics, statistics, and algorithm analysis.
• Permutation & Combination Calculator
  Calculate nPr (permutations) and nCr (combinations) with a step-by-step formula breakdown. Enter n and r to see the count, formula expansion, and intermediate values.
• Probability Calculator
  Calculate the probability of single events and combined events (and/or). Enter counts or fractions to find probability, odds, and complementary probability in one step.
• Standard Deviation Calculator
  Calculate population and sample standard deviation, variance, and mean for any data set. Paste numbers one per line or comma-separated — results and formula shown instantly.
• Triangle Calculator
  Solve any triangle from sides or angles using the law of sines and cosines. Enter any three values (SSS, SAS, ASA, AAS, or SSA) and get all remaining sides, angles, and area.
• Circle Calculator
  Calculate the area, circumference, diameter, and radius of a circle from any one known value. Instant results with formulas shown — useful for geometry, engineering, and design.
• Equation Solver
  Solve linear equations (ax + b = c) and quadratic equations (ax² + bx + c = 0) symbolically. Shows step-by-step working and real or complex roots for quadratics.
• Matrix Calculator
  Add, subtract, multiply, transpose, and invert matrices of any size. Shows intermediate steps for multiplication and Gaussian elimination for matrix inversion.
• Scientific Calculator
  Full scientific calculator with trigonometric functions (sin, cos, tan), logarithms, exponents, factorials, and constants. Supports degree and radian mode.

Convert between units of length, weight, temperature, and more.

• Length Converter
  Convert length between meters, feet, miles, kilometers, inches, centimeters, yards, and nautical miles. Instant results — useful for travel, construction, and international unit conversion.
• Weight Converter
  Convert weight between kilograms, pounds, ounces, grams, stones, and metric tons. Handles both metric and imperial units — useful for cooking, shipping, and fitness tracking.
• Area Converter
  Convert area between square meters, square feet, acres, hectares, square kilometers, and square miles. Useful for real estate, land measurement, and engineering projects.
• Volume Converter
  Convert volume between liters, gallons, milliliters, cubic meters, fluid ounces, cups, and pints. Handles both US and UK gallons — useful for cooking, chemistry, and engineering.
• Temperature Converter
  Convert temperature between Celsius, Fahrenheit, and Kelvin with instant results. Includes common reference points — freezing, body temperature, boiling — for quick sanity checks.
• Speed Converter
  Convert speed between mph, km/h, knots, m/s, and feet per second. Useful for travel, aviation, maritime, and physics — handles all common speed units instantly.
• Time Converter
  Convert time between seconds, minutes, hours, days, weeks, months, and years. Useful for project estimates, API timeout values, and unit conversions in calculations.
• Energy Converter
  Convert energy between joules, calories, kilocalories, kilowatt-hours, BTU, and electron volts. Useful for physics, nutrition, and engineering calculations.
• Power Converter
  Convert power between watts, kilowatts, megawatts, horsepower, BTU/hour, and foot-pounds per second. Useful for electrical engineering, automotive, and HVAC calculations.
• Force Converter
  Convert force between newtons, pounds-force, kilonewtons, dynes, and kilograms-force. Useful for physics, mechanical engineering, and structural calculations.
• Pressure Converter
  Convert pressure between pascals, bar, psi, atm, mmHg, and kilopascals. Useful for meteorology, hydraulics, pneumatics, and tire pressure conversions.
• Frequency Converter
  Convert frequency between hertz, kilohertz, megahertz, gigahertz, and RPM. Useful for electronics, signal processing, audio engineering, and mechanical rotation.
• Angle Converter
  Convert angles between degrees, radians, and gradians. Instant conversion with formulas shown — useful for trigonometry, navigation, engineering, and CAD work.
• Data Storage Converter
  Convert data storage between bytes, KB, MB, GB, TB, and PB — in both binary (1 KB = 1024 B) and decimal (1 KB = 1000 B) modes. Useful for storage planning and file size comparisons.
• Currency Converter
  Convert between 30+ world currencies using live exchange rates updated daily from the European Central Bank. No signup — get instant results for USD, EUR, GBP, JPY, INR, and more.
• Fuel Economy Converter
  Convert fuel economy between MPG (US and UK), L/100km, and km/L. Useful for comparing car specs across countries or understanding international fuel consumption ratings.
• Paper Size Converter
  Convert ISO A and B series paper sizes and US Letter, Legal, and Tabloid between millimetres, inches, points, and pixels at any DPI. Includes a full reference table of standard dimensions.
• Shoe Size Converter
  Convert shoe sizes between US, UK, EU, and foot length in cm — for both men's and women's sizing. Includes a full reference chart for all standard international shoe size systems.
• Clothing Size Converter
  Convert clothing sizes between US, UK, EU, and AU for men's and women's tops, bottoms, and dresses. Includes reference charts for chest, waist, and hip measurements.

Binary, hex, ASCII, and base converters.

• Binary ⇄ Decimal
  Convert between binary and decimal numbers in both directions. Supports signed integers and shows the step-by-step positional value breakdown for each conversion.
• Binary ⇄ Hex
  Convert between binary and hexadecimal notation. Handles any length input and groups binary output into nibbles (4-bit groups) for readability.
• Hex ⇄ Decimal
  Convert between hexadecimal and decimal numbers. Supports uppercase and lowercase hex input — useful for color codes, memory addresses, and network protocols.
• Octal ⇄ Decimal
  Convert between octal (base 8) and decimal (base 10). Useful for Unix file permissions, legacy computing, and programming exercises involving number systems.
• Number Base Converter
  Convert any number between any two bases from 2 (binary) to 36. Enter the source base, target base, and number — ideal for computer science and custom encoding schemes.
• ASCII Converter
  Convert text to ASCII character codes and ASCII codes back to text. Shows decimal, hexadecimal, and binary representations for each character simultaneously.
• Roman Numeral Converter
  Convert integers to Roman numerals and Roman numerals back to integers. Supports 1–3999 with proper subtractive notation (IV, IX, XL, XC, CD, CM).
• BCD Converter
  Convert decimal numbers to Binary-Coded Decimal (BCD) and back. Shows the 4-bit group encoding for each decimal digit — useful for electronics and embedded systems.

Passwords, IDs, QR codes, and more.

• Password Generator
  Generate strong, random passwords with custom length, uppercase, lowercase, numbers, and symbols. Built-in strength meter. Nothing is stored — all generation happens in your browser.
• UUID Generator
  Generate random UUID v4 strings instantly — one or in bulk. Copy-paste ready GUIDs for databases, APIs, and unique identifiers.
• QR Code Generator
  Create QR codes for URLs, plain text, phone numbers, or contact cards (vCard). Download as PNG. Free QR code generator — no signup, no watermark, works in your browser.
• Barcode Generator
  Generate EAN-13, EAN-8, UPC-A, Code 128, and Code 39 barcodes from any input. Download as SVG or PNG — useful for product labeling, inventory, and retail applications.
• Random Number Generator
  Generate a random number in any range — integers or decimals, with optional no-repeat mode. Useful for picking lottery numbers, random sampling, and game mechanics.
• Dice Roller
  Roll any combination of dice using standard RPG notation (e.g. 3d6, 2d10+5). Shows individual die results and totals — perfect for tabletop games and probability demonstrations.
• Coin Flipper
  Flip a virtual coin and track heads vs. tails statistics over many flips. Useful for teaching probability, settling disputes, or making random decisions quickly.
• Random Color Generator
  Generate a random color or a harmonious palette using complementary, triadic, or analogous color rules. Shows HEX, RGB, and HSL values — great for design inspiration.
• Random Name Generator
  Generate random first and last names from many cultures and regions — English, Spanish, Japanese, Chinese, and more. Useful for placeholders, test data, and creative writing.

Color, typography, spacing, and CSS generators.

• WCAG Contrast Checker
  Check foreground/background color contrast ratios against WCAG 2.1 AA (4.5:1) and AAA (7:1) standards. Enter HEX or RGB values — see pass/fail for normal and large text.
• CSS Gradient Generator
  Build linear and radial CSS gradients visually with a live preview and copy-ready CSS output. Control colors, stops, angle, and shape — no code required.
• Image Color Palette
  Extract a dominant color palette from any uploaded image. Shows the top colors with HEX values — useful for brand identity, design matching, and color inspiration.
• Box Shadow Generator
  Compose CSS box-shadow visually — adjust X/Y offset, blur, spread, and color with a live preview. Copy the final CSS rule with one click. Supports multiple shadow layers.
• Border Radius Generator
  Build CSS border-radius values visually — symmetric, asymmetric, or fully custom per-corner shapes. Live preview with copy-ready CSS output for any border-radius combination.
• Type Scale Generator
  Generate a modular type scale from a base font size and ratio (Major Third, Perfect Fourth, Golden Ratio, and more). Outputs CSS custom properties for a consistent typographic system.
• PX ↔ REM Converter
  Convert between pixels and rems for any base font size (default 16px). Paste a list of values to convert all at once — useful for responsive CSS and design token work.
• Spacing Scale Generator
  Build a consistent spacing scale for design systems — enter a base unit and multiplier to generate a full set of spacing tokens in px and rem, ready for Tailwind or CSS variables.
• Aspect Ratio Calculator
  Calculate width or height to preserve any aspect ratio — 16:9 widescreen, 4:3, 1:1, or custom. Great for responsive images, video embeds, and UI layouts.

Networking, certificates, hashing, and security utilities.

• Password Strength Checker
  Estimate password entropy and time-to-crack using the zxcvbn algorithm. Shows realistic crack time estimates under different attack scenarios — far more accurate than simple strength bars.
• Hash Generator
  Generate MD5, SHA-1, SHA-256, and SHA-512 hashes of any string. Useful for checksums, data integrity verification, and understanding hash output lengths for each algorithm.
• SSL Certificate Decoder
  Paste a PEM-encoded SSL/TLS certificate to inspect issuer, subject, SANs, validity period, public key, and signature algorithm. Everything runs in your browser — no certificate is uploaded.
• IP/CIDR Subnet Calculator
  Compute subnet range, network mask, broadcast address, and usable host count for any IPv4 CIDR block. Also shows all subnets when you split a block — useful for network planning.

Loans, taxes, salary, and everyday money decisions.

• Mortgage Calculator
  Calculate your monthly mortgage payment including principal, interest, taxes, and insurance (PITI). View full amortization schedule and see how extra payments affect payoff date.
• Loan Calculator
  Calculate monthly loan payment, total interest paid, and full amortization schedule for any loan amount, interest rate, and term. Works for auto loans, personal loans, and student loans.
• EAR ↔ APR Calculator
  Convert between APR and effective annual rate (EAR) at any compounding frequency — monthly, daily, continuous. Shows how compounding frequency changes the true cost of a loan.
• Salary Calculator
  Convert salary between hourly, daily, weekly, bi-weekly, monthly, and annual rates. Useful for comparing job offers, freelance rates, and understanding your true annual income.
• Tip Calculator
  Calculate tip amount and split the total bill between any number of people. Choose from common tip percentages or enter a custom rate — great for restaurants and group outings.
• Sales Tax Calculator
  Calculate sales tax on any purchase or reverse-calculate the pre-tax price from a total. Enter price and tax rate to see tax amount and final total — useful for any US state rate.
• Discount Calculator
  Calculate the final price after a percentage discount, the discount amount saved, and the effective discount rate from original and sale prices. Great for shopping and pricing decisions.
• Compound Interest
  Calculate future value with compound interest and optional monthly contributions. Shows year-by-year growth, total contributions, and total interest earned — useful for savings planning.
• ROI Calculator
  Calculate return on investment (ROI) in both absolute and annualized percentage form. Enter initial cost and final value to see simple ROI and CAGR for any holding period.
• CAGR Calculator
  Calculate compound annual growth rate (CAGR) from beginning value, ending value, and number of years. The standard metric for measuring consistent investment or business growth over time.
• Inflation Calculator
  Calculate how inflation erodes purchasing power over time. Enter an amount and two years to see the equivalent value in today's dollars — uses historical US CPI data.
• Margin & Markup Calculator
  Calculate gross margin percentage, markup percentage, and cost or sale price from any two known values. Understand the difference between margin (of revenue) and markup (of cost).
• Annuity Calculator
  Calculate present and future value of ordinary annuities and annuities due from payment, rate, and periods. Useful for valuing bonds, lease payments, pension income, and retirement planning.

Valuation, options, fixed income, and risk metrics for analysts.

• NPV & IRR Calculator
  Calculate net present value and internal rate of return for any series of cash flows. Enter a discount rate and yearly cash flows to evaluate whether an investment creates value.
• WACC Calculator
  Calculate weighted average cost of capital from equity cost, debt cost, tax rate, and capital structure weights. The standard discount rate for corporate DCF valuations.
• CAPM Calculator
  Calculate the required return on equity using CAPM: risk-free rate + beta × equity risk premium. Used to estimate cost of equity for WACC and to assess whether a stock is fairly valued.
• Bond Pricing & YTM
  Calculate bond price, yield to maturity, Macaulay duration, and convexity for any fixed-coupon bond. Supports semi-annual and annual coupons — useful for fixed income analysis.
• Black-Scholes Options Pricing
  Calculate call and put option prices and all five Greeks (delta, gamma, theta, vega, rho) using the Black-Scholes model. Enter spot price, strike, volatility, rate, and expiry.
• Sharpe Ratio Calculator
  Calculate the Sharpe ratio (risk-adjusted return) from a return series and risk-free rate. Paste portfolio returns to see mean return, standard deviation, and Sharpe ratio.

Ad math, conversion, A/B testing, and SEO helpers.

• SERP Snippet Preview
  Preview how your page title and meta description will appear in Google search results. Shows the rendered SERP snippet with character counts and truncation warnings.
• UTM Link Builder
  Build clean UTM-tagged campaign URLs for Google Analytics tracking. Enter source, medium, campaign, term, and content — get a properly encoded URL to paste into your ads or emails.
• CPM / CPC / CTR Calculator
  Convert between impressions, clicks, cost, CTR, CPM, and CPC for any ad campaign. Enter any two values to calculate the others — useful for planning and evaluating digital ad buys.
• ROAS Calculator
  Calculate return on ad spend (ROAS), cost per acquisition (CPA), and the break-even ROAS needed to cover your cost of goods. Essential for evaluating paid search and social campaigns.
• Conversion Rate Calculator
  Compute conversion rates from visitors and conversions, compare two rates, and calculate the confidence interval around each estimate. Useful for landing page and funnel analysis.
• A/B Test Significance
  Run a two-proportion z-test on A/B test results. Enter visitors and conversions for each variant to see p-value, statistical significance, relative lift, and minimum sample size guidance.
• LTV / CAC Calculator
  Calculate customer lifetime value (LTV), customer acquisition cost (CAC), LTV:CAC ratio, and CAC payback period. Core SaaS and e-commerce metrics for assessing unit economics.

Clinical formulas, dosing, and physiology calculators.

• BMI Calculator
  Calculate Body Mass Index (BMI) in metric (kg/cm) or imperial (lbs/in). Instantly shows your BMI value and weight category — underweight, normal, overweight, or obese.
• Body Surface Area (BSA)
  Calculate body surface area using the Mosteller and DuBois formulas. Used clinically for chemotherapy dosing, burn assessment, and cardiac output calculations.
• Ideal Body Weight
  Calculate ideal body weight using the Devine, Robinson, and Hamwi formulas in metric and imperial units. Used in clinical dosing and nutritional assessment.
• Target Heart Rate Zones
  Calculate heart rate training zones using the Karvonen formula from your age and resting heart rate. Shows 5 zones from light aerobic to maximum effort for exercise planning.
• eGFR Calculator
  Calculate estimated glomerular filtration rate (eGFR) using the CKD-EPI 2021 equation. Used to stage chronic kidney disease from serum creatinine, age, and sex.
• Creatinine Clearance
  Calculate creatinine clearance using the Cockcroft-Gault equation with optional adjusted body weight. Widely used for drug dose adjustments in renal impairment.
• Pregnancy Due Date
  Calculate estimated due date (EDD) and current gestational age using Naegele's rule from last menstrual period. Shows trimester and key milestone dates.
• Pediatric Dose (mg/kg)
  Convert weight-based mg/kg doses to total dose in mg or mL. Includes maximum dose safety checks — useful for nurses, pharmacists, and physicians calculating pediatric drug doses.
• IV Drip Rate
  Calculate IV drip rate in drops per minute and flow rate in mL/hr for any infusion. Enter volume, time, and drop factor — essential for nursing and pharmacy calculations.
• Anion Gap Calculator
  Calculate the anion gap from sodium, chloride, and bicarbonate, with optional albumin correction. Used to diagnose and classify metabolic acidosis in clinical settings.
• CHA₂DS₂-VASc Score
  Calculate the CHA₂DS₂-VASc stroke risk score for patients with atrial fibrillation. Shows score, annual stroke risk percentage, and anticoagulation threshold guidance.
• MELD Score
  Calculate the Model for End-Stage Liver Disease (MELD) score from bilirubin, creatinine, and INR. Used to prioritize liver transplant candidates by disease severity and 90-day mortality risk.
• Wells PE Score
  Calculate the Wells clinical prediction score for pulmonary embolism probability. Stratifies patients into low, intermediate, and high pre-test probability to guide imaging decisions.

Merge, split, convert, and edit PDF files — all in your browser.

• PDF Merge
  Combine multiple PDF files into one document. Drag to reorder pages, then download the merged PDF — no upload, processed entirely in your browser.
• PDF Split
  Split a PDF by page ranges or extract individual pages. Enter ranges like 1-3,5,7-9 or extract every page as a separate file — processed in your browser.
• PDF to Images
  Convert PDF pages to PNG or JPG images. Renders each page as a high-quality image you can download individually or as a ZIP — runs entirely in your browser.
• Images to PDF
  Convert JPG, PNG, or WebP images to a PDF document. Drag to reorder, choose page size and orientation, then download the PDF — no upload, runs in your browser.
• PDF Rotate
  Rotate PDF pages by 90°, 180°, or 270°. Apply rotation to all pages or specific pages — download the corrected PDF instantly, processed in your browser.
• PDF Compress
  Reduce PDF file size by recompressing the document structure. No external server — compressed and downloaded directly in your browser.
• PDF Metadata Viewer
  View PDF metadata: title, author, creator, producer, creation date, modification date, and page count — instantly parsed in your browser without uploading anywhere.

Practical calculators for circuits and electronics.

• Ohm's Law Calculator
  Solve Ohm's Law (V = IR) for voltage, current, or resistance — enter any two values to find the third. Also calculates power (W) from the known values.
• Watts to Amps
  Convert between watts, amps, and volts for AC and DC circuits. Handles single-phase and three-phase AC with power factor — useful for electrical load planning and wiring.
• Power Calculator
  Calculate electrical power in watts from any two of voltage, current, or resistance. Uses P = VI, P = V²/R, and P = I²R — useful for circuit design and energy estimation.
• kVA Calculator
  Calculate kVA, kW, and amperage for single-phase and three-phase electrical systems. Enter any two values to find the third — useful for generator sizing and transformer selection.
• Voltage Divider
  Calculate the output voltage of a two-resistor voltage divider. Enter input voltage and both resistor values — useful for sensor biasing, ADC reference voltages, and signal conditioning.
• Resistor Color Code
  Decode 4-band, 5-band, and 6-band resistor color codes to find resistance in ohms, tolerance, and temperature coefficient. Also converts a resistance value to color bands.
• Capacitor Calculator — Series & Parallel Capacitance
  Calculate equivalent capacitance for capacitors in series and parallel, plus RC time constants. Enter values, get total capacitance instantly — free, no signup.
• Inductance Calculator
  Calculate inductive reactance (XL) and energy stored in an inductor from inductance and frequency. Also computes resonant frequency for LC circuits.
• Decibel Calculator
  Calculate decibels (dB) from voltage ratios, power ratios, or amplitude ratios — and convert dB values back to linear ratios. Covers dBV, dBm, and dBW standards.
• AWG Wire Size
  Look up American Wire Gauge (AWG) specifications: diameter in mm, cross-section in mm², resistance per meter, and maximum ampacity for chassis and power wiring.