Significant Figures Calculator
Count sig figs and round to any precision.
Enter your values
ⓘ Live results
Results
- Significant figures
- 5
- Rounded to 3 sig figs
- 0.0043
- In scientific notation
- 4.30e-3
- Decimal places in original
- 7
Working
- 1Leading zeros never count; trailing zeros count only after a decimal point.
Quick answer
Significant figures are the digits that carry meaning: all non-zero digits, zeros between them, and trailing zeros after a decimal point.
How to use the Significant Figures Calculator
- 1Type the number exactly as written, keeping trailing zeros.
- 2Choose how many sig figs to round to.
- 3Read the count and rounded value.
Worked example
Using the values the calculator loads with:
Inputs
- Number0.0043020
- Round to how many sig figs3
Results
- Significant figures5
- Rounded to 3 sig figs0.0043
- In scientific notation4.30e-3
- Decimal places in original7
- Leading zeros never count; trailing zeros count only after a decimal point.
Frequently asked questions
Do trailing zeros count?
After a decimal point yes — 2.500 has four sig figs. In a whole number like 2500 they are ambiguous without scientific notation.
Which rule applies to multiplication?
The answer carries the same number of sig figs as the least precise factor. For addition, match decimal places instead.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.