Tools / Rounding calculator (decimals & significant figures)
Rounding calculator
Enter a number and choose how many decimal places or significant figures you need.
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🔒 Runs entirely in your browser – nothing you enter is uploaded or stored.
How to use it
- Enter the number.
- Choose decimal places, significant figures or a multiple.
- Read all rounded values.
Your inputs live only in the link, not on our server.
Last checked: October 2026. Found a mistake? Use the form below – we fix confirmed errors and update the date.
Frequently asked questions
How do you round to two decimal places?
Look at the third decimal: 5 or more rounds up, otherwise down – 3.14159 → 3.14.
What are significant figures?
All digits from the first non-zero digit: 0.0305 has three significant figures (3, 0, 5).