Significant Figures Calculator

How significant figures work

Significant figures (sig figs) are the meaningful digits in a measured or calculated number. The rules: all non-zero digits are significant; zeros between non-zero digits are significant; leading zeros are never significant; trailing zeros after a decimal point are significant; trailing zeros in a whole number are ambiguous unless a decimal point is shown. When rounding to N sig figs, find the magnitude (log₁₀), then round to N−1−magnitude decimal places. Scientific notation always makes the count unambiguous.