Rounding Calculator
Round numbers to nearest decimal places, whole numbers, significant figures, or specific multiples. Simple and precise mathematical rounding tool.
0 for whole number, 1 for tenths, etc.
Rounding Methods Explained
Rounding to Decimals
This method rounds a number to a specified number of digits after the decimal point. The standard rule is "round half up": if the next digit is 5 or more, round up. Otherwise, round down.
- 3.14159 to 2 decimal places → 3.14
- 3.14159 to 3 decimal places → 3.142
Rounding to Nearest Multiple
This rounds a number to the nearest multiple of a specific value (integer or fraction). This is useful for currency (nearest cent/dollar) or construction measurements.
- 123 to nearest 5 → 125
- 123 to nearest 10 → 120
- 0.73 to nearest 0.25 → 0.75
Significant Figures
Rounding to significant figures is used in science and engineering to express precision. It counts digits from the first non-zero digit.
- 12345 to 3 sig figs → 12300
- 0.0012345 to 2 sig figs → 0.0012
? Frequently Asked Questions
Yes. This is the standard rounding method taught in schools (e.g., 2.5 becomes 3, 2.4 becomes 2). It matches the behavior of the `Math.round()` function in programming.
Select 'Decimals' mode and set the target to 0. Or select 'Nearest Multiple' and set the target to 1.
Yes, the calculator handles negative numbers correctly using symmetric rounding logic (rounding away from zero for halves in magnitude).