Round any number your way. This free rounding calculator rounds to decimal places or the nearest 10/100/1,000, with standard, banker’s, ceiling, floor and truncate methods.
Choose how precise you want the result and which rounding method to use. “Round half up” is the everyday default; “banker’s rounding” rounds halves to the nearest even digit.
Rounding replaces a number with a simpler nearby value at the chosen precision. The method matters only when the digit is exactly halfway (a 5).
How the Rounding Calculator Works
Rounding simplifies a number to a chosen level of precision, whether that’s a number of decimal places or the nearest 10, 100, or 1,000. This calculator supports five different rounding methods, since the “right” answer for a number sitting exactly halfway between two values depends on which convention you’re using.
Formula: Scale the number by the chosen place value, factor = 10^p (where p is the number of decimal places, or negative for nearest 10/100/1,000), then apply the rounding method to x × factor, then divide back by factor. Round half up rounds a halfway value away from zero (2.5 → 3). Round half to even (banker’s rounding) rounds a halfway value to whichever neighbor is even (2.5 → 2, but 3.5 → 4). Ceiling always rounds toward positive infinity, floor always rounds toward negative infinity, and truncate simply drops the digits past the chosen place without rounding at all.
- Number — the value you want to round
- Round to — the precision: nearest whole number, 1-4 decimal places, or nearest 10/100/1,000
- Rounding method — how halfway cases are resolved: half up, half to even (banker’s), ceiling, floor, or truncate
Example Scenarios
| Number | Round To | Method | Result |
|---|---|---|---|
| 3.14159 | 2 decimal places | Half up (standard) | 3.14 |
| 2.5 | Nearest whole number | Half up (standard) | 3 |
| 2.5 | Nearest whole number | Half to even (banker’s) | 2 |
| 3.5 | Nearest whole number | Half to even (banker’s) | 4 |
| -3.7 | Nearest whole number | Ceiling (always up) | -3 |
| -3.7 | Nearest whole number | Floor (always down) | -4 |
Rounding Calculator FAQ
What’s the difference between “round half up” and banker’s rounding?
Round half up always pushes an exact halfway value away from zero, so 2.5 becomes 3. Banker’s rounding (half to even) instead rounds to whichever neighboring number is even, so 2.5 becomes 2 while 3.5 becomes 4. Banker’s rounding is used in some financial and statistical contexts to avoid a consistent upward bias.When should I use ceiling or floor instead of standard rounding?
Use ceiling when you always need to round up regardless of the decimal — for example, calculating how many boxes are needed to fit a certain quantity. Use floor when you always need to round down, such as counting how many complete units fit into a total.How is “truncate” different from rounding down?
Truncating just deletes the digits past the chosen place value without any rounding logic, which for positive numbers looks identical to flooring. The difference shows up with negative numbers: floor(-3.7) is -4, but truncating -3.7 gives -3, since truncation always moves toward zero.How do I round a number to the nearest 100 or 1,000 instead of a decimal place?
Choose “Nearest 100” or “Nearest 1,000” from the Round To list instead of a decimal-place option. These use a negative place value internally, so the calculator scales the number down by 100 or 1,000, rounds it, and scales it back up.Why do 2.5 and 3.5 round to different results under banker’s rounding?
Banker’s rounding resolves every halfway case by choosing the nearest even number. 2 is even and 3 is odd, so 2.5 rounds down to 2. 4 is even and 3 is odd, so 3.5 rounds up to 4. Over many values this evens out rounding bias in either direction.Does rounding work correctly with negative numbers?
Yes, all five methods handle negative numbers, but “up” and “down” mean different things depending on the method. Ceiling always moves toward positive infinity (so -3.7 rounds to -3), while floor always moves toward negative infinity (so -3.7 rounds to -4).Related Calculators
Choosing how to round often ties into choosing how much precision to keep in the first place — the significant figures calculator and the scientific notation converter both help with that, while the exponent calculator is handy when the numbers you’re rounding come from a power calculation.