Significant Figures Calculator
Free significant figures calculator — count the sig figs in any number and round it to a chosen number of significant figures.
Everyday Uses
Lab reports
Report measurements to the correct precision every time.
Chemistry & physics
Count sig figs and round answers properly for marks.
Measurement
Match your answer's precision to your instruments.
Rounding
Round any value to a set number of significant figures.
Frequently Asked Questions
What are significant figures?
Significant figures are the digits in a number that carry real, reliable information about its precision. All non-zero digits count, zeros between non-zero digits count, and trailing zeros after a decimal point count. Leading zeros never count. 0.004560 has four significant figures: 4, 5, 6, and the final 0.
How do you round to significant figures?
Keep the required number of significant digits, starting from the first non-zero digit, and round the rest away using the next digit. 3.14159 to three sig figs is 3.14; 0.0028471 to two sig figs is 0.0028. This calculator does the counting and rounding for you.
Are trailing zeros significant?
It depends on the decimal point. In 1.500 the trailing zeros are significant (four sig figs). In a plain integer like 1500 they are ambiguous — they may just mark the magnitude. To show they are significant, write the number in scientific notation, e.g. 1.500 × 10³.