Significant Figures Calculator

Significant figures (sig figs) are the digits in a number that carry meaningful information about its precision. They include all non-zero digits, zeros between non-zero digits, and trailing zeros after the decimal point. Leading zeros are never significant.

1. All non-zero digits are significant. 2. Zeros between non-zero digits are significant (1001 has 4 sig figs). 3. Leading zeros are not significant (0.0045 has 2 sig figs). 4. Trailing zeros after a decimal point are significant (3.50 has 3 sig figs). 5. Trailing zeros in whole numbers are ambiguous without a decimal point.

Identify the position of the last significant digit you want to keep. Look at the next digit: if 5 or greater, round up; if less than 5, round down. For example, 0.005678 to 2 sig figs: the first two sig figs are 5 and 6, the next digit is 7 (≥5), so round up: 0.0057.

The result should have the same number of significant figures as the input with the fewest sig figs. Example: 2.5 × 3.42 = 8.55 → round to 2 sig figs (limited by 2.5) = 8.6.

The result should have the same number of decimal places as the input with the fewest decimal places. Example: 12.52 + 1.7 = 14.22 → round to 1 decimal place (limited by 1.7) = 14.2.