✓ Effortless Math · Free Tool

Significant Figures Calculator

Enter a number to count its significant figures using the standard rules, round it to any number of sig figs, and see which digit is the last significant one — with step-by-step working.

Leading zeros don't count · trapped zeros do · trailing zeros count with a decimal point
number round to sig figs N sig figs

Type a plain decimal (e.g. 0.004560) or scientific notation (e.g. 4.56e-3). The round to N field is optional. Trailing zeros count only when a decimal point is shown.

Results

Significant figures
—
—
Sig-fig count
—
Rounded to N sig figs
—
Place of last significant digit
—

Step-by-step