Logo

Rounding Calculator

Round numbers to decimal places, significant figures, or the nearest power of ten.

Enter a number and select options to see the result.

How to Use

  1. Enter the number you want to round in the Enter Number field.
  2. Select the Rounding Method from the dropdown.
  3. If needed, specify Decimal Places or Significant Figures.
  4. The rounded result will appear automatically below.
  5. Use Clear to reset the input and result fields.

How the Calculator Works

The calculator uses standard rounding functions based on your selected method:

  • Decimal Places: Uses toFixed() to round to a set number of decimal places.
  • Significant Figures: Uses toPrecision() to round to a set number of significant digits.
  • Nearest Ten/Hundred/etc.: Rounds to the nearest multiple of 10, 100, 1000, etc.

Input validation ensures you enter a valid number and appropriate precision before calculation.

Frequently Asked Questions (FAQ)

What is the difference between decimal places and significant figures?

Decimal places count digits after the decimal point. Significant figures count all digits starting from the first non-zero digit.

Why does the precision input disappear for rounding to tens/hundreds?

Precision is only needed for decimal places or significant figures. For other methods, the rounding target is fixed.

Can I round negative numbers?

Yes, negative numbers are handled correctly for all rounding methods.

What happens if I enter text instead of a number?

An error message will prompt you to enter a valid number.

How are numbers exactly halfway between rounded?

Standard "round half up" rules are used (e.g., 15 rounds to 20, -1.5 rounds to -2).

Why does the result sometimes appear in scientific notation?

Very large or small numbers may be displayed in scientific notation, especially with significant figures.

Are there different ways to round?

This calculator uses the common "round half up" method. Other rounding methods are not currently supported.

Try More Free Tools!

Explore our full collection of developer, text, and media tools to boost your productivity.

Browse All Tools