Rounding without surprises
Rounding replaces a number with a simpler, nearby one. You can round to a number of decimal places, to a number of significant figures, or to the nearest multiple such as 5, 10, 0.05 or 250.
Different fields use different rules for a tie like 2.5: standard half-up gives 3, while banker's rounding (half to even) gives 2 to avoid a systematic upward bias. This calculator supports seven rules and works on the exact digits you typed, so 1.005 correctly rounds to 1.01.
How it is calculated
Look at the digit just after the place you keep
5 or more: round up (half-up rule)
Below 5: leave the digit as it is
Worked example
1234.5678
- 2 decimal places
- 1234.57
- 3 significant figures
- 1230
- Nearest 10
- 1230
- Whole number
- 1235
Rounding rules compared for 2.5 and −2.5
| Rule | 2.5 | −2.5 |
|---|---|---|
| Half up | 3 | −2 |
| Half to even | 2 | −2 |
| Ceiling | 3 | −2 |
| Floor | 2 | −3 |
| Truncate | 2 | −2 |
| Away from zero | 3 | −3 |