How do I round to a number of decimal places?

Choose Decimal places as the target and select 0 to 4. Rounding 3.14159 to 2 decimals gives 3.14.

What does rounding to the nearest 10 or 100 mean?

It replaces the number with the closest multiple of that step. The nearest 10 to 1,234 is 1,230; the nearest 100 is 1,200.

How are exact halves rounded?

By default the Nearest direction rounds halves up, so 2.5 becomes 3. Choose Round up or Round down if you need a fixed direction.

What is the difference value?

It is the rounded value minus your original value. A positive difference means rounding moved the number up; a negative one means it moved down.

Does it work with negative numbers?

Yes. Round up moves towards positive infinity and round down towards negative infinity, so −2.5 rounds up to −2 and down to −3.

Can I share a calculation?

Yes. Use Share to copy a link that reopens the calculator with the same value and rounding settings.

Rounding calculator

Enter a number, choose how to round it, and see the rounded value and how far it moved as you type.

Use it to round a number to decimal places or to the nearest 1, 10, 100 or 1000, either to the nearest value or always up or down.

Value to round

Round to

Decimal places

Direction

Rounded value

3.14

Difference: -0.00159

The result updates as you type. The number line shows the original value and where it lands after rounding.

How does it work?

round() depends on the direction: round half up for nearest, ceiling for up, floor for down.

Rounding formula

\begin{aligned} &\text{rounded} = \operatorname{round}\!\left(\tfrac{x}{u}\right) \times u\\[2pt] &\text{difference} = \text{rounded} - x \end{aligned}

x: The original value you enter.
u: The rounding unit: 10⁻ⁿ for n decimal places, or the chosen step (1, 10, 100, 1000).

Rounding 2.5 to the nearest whole number (u = 1) gives 3.

Method & sources

A single value is rounded to one chosen target: a number of decimal places, or the nearest 1, 10, 100 or 1000. Half values round up by default; choose Round up or Round down for one-directional rounding. The number format shown follows the site language; the rounding math is the same in every market.

Sources

Where this method comes from — use these references to understand the formula, assumptions, and limits.

Rounding rules — IEEE and standard practice — National Institute of Standards and Technology, verified 2026-06-10

How we calculate

A single value is rounded to one chosen target: a number of decimal places, or the nearest 1, 10, 100 or 1000.
Half values round up by default; choose Round up or Round down for one-directional rounding.
The number format shown follows the site language; the rounding math is the same in every market.

Rounding

Nearest uses round-half-up, so an exact half always goes to the higher value (2.5 → 3). Up rounds towards positive infinity and down towards negative infinity. Display values are trimmed to at most six decimals to avoid floating-point noise.

What this calculator does

Rounding replaces a number with a nearby, simpler one. This calculator rounds to a chosen number of decimal places or to the nearest 1, 10, 100 or 1000, and lets you round to the nearest value or always up or down.

How to use it

Enter the value you want to round.
Choose decimal places or a nearest multiple as the target.
Pick a direction: nearest, round up, or round down.
Read the rounded value and the difference from the original below.

A worked example

Rounding 3.14159 to 2 decimal places gives 3.14, a difference of −0.00159. Rounding 1,250 to the nearest 100 gives 1,300 with a difference of +50.

How halves are handled

With the Nearest direction, an exact half rounds up: 2.5 becomes 3 and 0.5 becomes 1. If you need to always round in one direction regardless of the half, choose Round up or Round down.

When it's useful

Tidying measurements, presenting prices and totals, simplifying statistics, and matching the precision required by a form or report.

FAQ

How do I round to a number of decimal places?: Choose Decimal places as the target and select 0 to 4. Rounding 3.14159 to 2 decimals gives 3.14.
What does rounding to the nearest 10 or 100 mean?: It replaces the number with the closest multiple of that step. The nearest 10 to 1,234 is 1,230; the nearest 100 is 1,200.
How are exact halves rounded?: By default the Nearest direction rounds halves up, so 2.5 becomes 3. Choose Round up or Round down if you need a fixed direction.
What is the difference value?: It is the rounded value minus your original value. A positive difference means rounding moved the number up; a negative one means it moved down.
Does it work with negative numbers?: Yes. Round up moves towards positive infinity and round down towards negative infinity, so −2.5 rounds up to −2 and down to −3.
Can I share a calculation?: Yes. Use Share to copy a link that reopens the calculator with the same value and rounding settings.

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