Toolono
Developer Tools View All Developer Tools
Date & Time View All Date & Time Tools
Text Tools View All Text Tools
Online Converters View All Online Converters
Math Tools View All Math Tools

Rounding Calculator

Round a number to a chosen precision with nearest, up, or down rules, then review the method and difference.

Round a number

Round a number to a chosen precision and method in one focused calculator.

Round decimals, whole numbers, tens, or hundreds without guessing

Enter one number, choose how many decimal places to keep, and select whether to round to the nearest value, round up, or round down. Negative precision is supported for rounding to tens or hundreds.

Enter a number and choose a precision to round it instantly.

Rounded result

Review the rounded value first, then confirm the original number, precision, method, and difference.

Ready

Enter a number to round it.

The rounded value will appear here as soon as the current inputs are valid.

Choose a precision and a rounding rule to see how the number changes.

How to use the rounding calculator

  1. Enter the number you want to round.
  2. Enter the decimal places to keep. Use negative values to round to tens or hundreds.
  3. Choose whether to round to the nearest value, round up, or round down.
  4. Review the rounded result first, then confirm the original value, precision, method, and difference.
  5. Use Example to load a sample number or Clear to reset the calculator.

Rounding calculator examples

  • round 12.3456 to 2 decimal places

  • round 1487 to the nearest hundred

  • round 9.01 up to 1 decimal place

  • round 9.09 down to 1 decimal place

  • how to round a number to the nearest tenth

What this rounding calculator covers

This tool rounds one number at a chosen precision using a clear rounding rule. It supports ordinary decimal rounding as well as negative precision for rounding to tens, hundreds, and thousands.

Rounding example result

Input: 12.3456

Precision: 2 decimal places

Mode: Nearest

Result: 12.35

Nearest vs round up vs round down

Nearest uses the closest matching value at the selected precision. Round up uses the next value toward positive infinity. Round down uses the next value toward negative infinity. Seeing all three as named rules makes it easier to avoid mixing up ordinary rounding with ceil or floor behavior.

When a rounding calculator is useful

A rounding calculator is useful for prices, measurements, reporting, schoolwork, estimates, and quick decimal cleanup. It is especially helpful when you need to round to a specific number of decimal places or to the nearest ten or hundred without opening a spreadsheet.

Rounding calculator FAQs

Can I round to tens or hundreds?

Yes. Use negative decimal places. For example, `-1` rounds to the nearest 10 and `-2` rounds to the nearest 100.

What is the difference between round up and round down?

Round up uses the next value toward positive infinity. Round down uses the next value toward negative infinity. They are not the same as ordinary nearest-value rounding.

Does this tool support decimal inputs?

Yes. Decimals and negative numbers are supported as long as the number itself is valid and the precision is a whole number.