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.
Result
3.14
How to use the rounding calculator
Enter a number, choose the place to round to, and pick a mode (nearest, up, down, or truncate toward zero).
Formula & explanation
Multiply by 10^(−place), apply the rounding function, divide back. Place: −2 = hundredths, 0 = ones, 2 = hundreds.
Examples
3.14159 → nearest hundredth = 3.14. 7.6 → round down = 7. −7.6 truncate = −7, floor = −8.
Frequently asked questions
- What is the difference between floor, ceil, and truncate?
- Floor always rounds toward negative infinity (floor(−7.2) = −8). Ceil always rounds toward positive infinity (ceil(−7.2) = −7). Truncate drops the decimal toward zero (trunc(−7.2) = −7).
- What does 'round to nearest' mean for halfway values?
- This calculator uses 'half away from zero': 2.5 rounds to 3, and −2.5 rounds to −3. Some systems use 'half to even' (banker's rounding) which rounds 2.5 to 2.
- How do I round to the nearest hundred or thousand?
- Set the place to 10^2 (hundreds) or 10^3 (thousands). For example, 3,741 rounded to the nearest hundred is 3,700.
- Why does rounding cause floating-point oddities?
- Floating-point arithmetic (IEEE 754) cannot represent all decimals exactly, so you may see results like 3.1400000000000001. This is a known property of binary floating-point, not a bug.
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