Rounding Calculator

Round numbers by decimals, significant figures or nearest multiple.

Rounded to 2 decimal places

3.14

from 3.14159

Original value

3.14159

Rounding error

-0.00159

Rounded down

Rounded up

3.15

Rounded down

3.14

Stored value

3.1415899999999999

How the number is actually held in binary

Multiply, round, divide back — the standard approach for decimal rounding.

Some decimals cannot be represented exactly in binary floating point, which is why 1.005 does not round to 1.01. The stored value row shows what is really there.
Switch to half-to-even for financial and statistical work.

What does Rounding Calculator do?

Round a number to a set number of decimal places, to significant figures, or to the nearest multiple — with a choice of rounding mode including banker’s rounding, which is what finance and statistics require.

How to Use Rounding Calculator

1
Enter a numberOr a list in batch mode.
2
Choose what to round toDecimals, significant figures or a multiple.
3
Pick a modeHalf-up is the everyday default.

Key Features

Round by decimal places, significant figures or nearest multiple
Five modes: half-up, half-even, up, down and toward zero
Rounding error shown alongside the result
Explains which mode suits finance, statistics and general use
Batch mode for rounding a whole list

Frequently Asked Questions

What is banker’s rounding?

Round-half-to-even: exact halves go to the nearest even number, so 2.5 becomes 2 and 3.5 becomes 4. It removes the upward bias of always rounding halves up, which is why accounting and statistics standards specify it.

How do I round to significant figures?

Count from the first non-zero digit. 0.004567 to two significant figures is 0.0046. It differs from decimal-place rounding, which would give 0.00 — significant figures preserve precision regardless of magnitude.

Why does 1.005 not round to 1.01?

Because 1.005 cannot be represented exactly in binary floating point — the stored value is fractionally below 1.005, so it rounds down. It is the single most common floating-point surprise, and the tool shows the actual stored value.

When should I round to a multiple?

Pricing to the nearest 5 or 99, scheduling to the nearest 15 minutes, or ordering in packs. Rounding 47 to the nearest 5 gives 45; to the nearest 10, 50.

Runs in your browser

All arithmetic runs in your browser, using exact BigInt maths where whole numbers are involved so nothing is lost to floating-point rounding.

How the rest of the site handles data