Significant Figures Calculator
Round to Any Sig Figs ⚡
Enter any number and choose how many significant figures to round to. Shows full working and identifies each significant figure.
Enter any number and choose how many significant figures to round to. Shows full working and identifies each significant figure.
Why do significant figures matter?
Significant figures communicate the precision of a measurement. Reporting too many figures implies false precision; too few loses information. In science and engineering, results should be reported to the same number of significant figures as the least precise measurement used.
What is the difference between significant figures and decimal places?
Decimal places count digits after the decimal point. Significant figures count meaningful digits starting from the first non-zero digit. 0.00456 has 3 significant figures but 5 decimal places.
How do I round to significant figures?
Find the nth significant figure, look at the next digit — if it is 5 or more, round up; if less than 5, round down. Replace all following digits with zeros (or remove if after a decimal point).