Significant Figures Calculator
Count sig figs and round any number to a set number of significant figures.
What is a significant figures calculator?
A significant figures calculator counts how many significant figures a number has and rounds it to the number of significant figures you choose.
How to use the significant figures calculator
Enter the number and how many significant figures to round to, then click Calculate. The calculator shows the count and the rounded number.
Significant figures rules
Leading zeros do not count. Trailing zeros after a decimal point do count. Zeros between digits count, and all non-zero digits count.
Example
0.00450 has 3 significant figures: 4, 5 and 0. The leading zeros do not count, but the trailing zero after the decimal point does. Rounded to 3 sig figs, it is 0.0045.
Frequently Asked Questions
How many significant figures does 0.00450 have?
0.00450 has 3 significant figures. Try it on the calculator above.
Do leading zeros count as significant figures?
No. Leading zeros only show where the decimal point is, so they do not count as significant figures.
What is 0.00450 rounded to 3 significant figures?
0.00450 rounded to 3 significant figures is 0.0045. Try it on the calculator above.
Browse more calculators: Math Calculators · All Tools