Rounding Tool
Choose a rounding mode, enter a finite number from −1e15 to 1e15, and get a predictable result for decimal and negative values.
A QUICK WALKTHROUGH
How to use this tool
- Choose decimal places or nearest multiple.
- Enter the value and rounding setting.
- Read or copy the rounded result.
Decimal places
Rounds to 0–15 digits after the decimal point. Half values use an explicit round-half-away-from-zero policy rather than native Math.round, whose negative ties move toward positive infinity.
Nearest multiple
Rounds value / multiple to the nearest integer, then multiplies back. The multiple must be finite and non-zero.
Input bounds
The input value must be finite and between −1e15 and 1e15. Calculations run locally.
GOOD TO KNOW
Common questions
How are negative half values rounded?
Away from zero: −2.5 becomes −3 and 2.5 becomes 3.
Can I round to a fraction or increment?
Yes. Use nearest-multiple mode with a non-zero finite multiple such as 0.25 or 5.
Does it change my input?
No. Everything runs locally in your browser and only displays the calculated result.