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Percentage Calculator
Find a percentage of a number, what percent one number is of another, or the whole from a part.
Significant Figures Calculator
Count the significant figures in a number and round it to any number of significant figures.
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How to use this calculator
Enter your values. The result updates as you type; press Calculate to confirm and jump to the result on mobile. Use Share to send the calculator with your result.
Rules for significant figures
- All non-zero digits are significant (123 → 3).
- Zeros between non-zero digits are significant (1005 → 4).
- Leading zeros are not (0.0045 → 2).
- Trailing zeros after a decimal point are (4.50 → 3).
- Trailing zeros in a whole number without a decimal point are ambiguous (1200 → 2, 3 or 4).
Example: 0.004050 has 4 significant figures (4, 0, 5, 0).
Frequently asked questions
How many sig figs in 100?
One, unless a decimal point is written (100. has three).
About this tool
- Written by
- [Author: to be assigned]
- Reviewed by
- Formula tests passed · human review pending
- Last updated
- 31 Oct 2026
See our methodology and editorial policy. Think something’s off? Report an error with this tool.
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