🧮 Rounding Calculator

About this Rounding Calculator

Different jobs round differently. Shops and school maths round halves up; programmers floor and ceiling; banks use banker's rounding so halves even out over thousands of transactions instead of always creeping up. Pick your mode and decimal places and see exactly what your number becomes — with a plain-language explanation of the result.

How to use it

1. Type the number to round (decimals welcome).
2. Choose how many decimal places to keep, from 0 to 10.
3. Select the rounding mode.
4. Click Round it and compare with the original.

Example

Rounding 2.5 to 0 places gives 3 with half-up, but 2 with banker's rounding (2 is even); 3.5 gives 4 under both.

Frequently asked questions

Why do banks use banker's rounding?

Always rounding halves up slightly inflates totals over millions of transactions. Rounding halves to even is unbiased — half go up, half go down.

Why did 2.675 round to 2.67 instead of 2.68?

Computers store 2.675 as a binary fraction that is actually a hair below 2.675, so the 'half' case never quite happens. Dedicated decimal libraries avoid this; everyday tools share the quirk.

More Calculators