Significant Figures Calculator
Count the significant figures in any number and round to your required precision. Essential for science and engineering.
Rules for Counting Sig Figs
- All non-zero digits are significant (e.g. 123 → 3 sig figs)
- Zeros between non-zeros are significant (e.g. 1002 → 4 sig figs)
- Leading zeros are NOT significant (e.g. 0.0045 → 2 sig figs)
- Trailing zeros after a decimal point ARE significant (e.g. 1.500 → 4 sig figs)
Examples
| Number | Sig Figs | Reason |
|---|
| 2500 | 2 | Trailing zeros without decimal ambiguous |
| 2500. | 4 | Decimal point makes all zeros significant |
| 0.00340 | 3 | Leading zeros not significant; trailing zero is |
| 1.0200 | 5 | All digits significant |
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