Significant Figures Calculator
Use this significant figures calculator to count the significant digits in a number and round the value to a chosen number of significant figures. It also shows scientific notation and explains how leading, internal and trailing zeros are treated.
How to use the Significant Figures Calculator
- Enter the number you want to analyze.
- The calculator removes non-significant leading zeros and identifies digits that contribute to measurement precision.
- Choose how many significant figures the rounded result should contain.
- The calculator determines the decimal position required for that precision and rounds the number.
- Review the significant-figure count, rounded value and scientific-notation form.
Examples
0.00450
The leading zeros are placeholders, while 4, 5 and the trailing decimal zero are significant. The value therefore has 3 significant figures.
123.456 to 4 significant figures
123.456 rounded to 4 significant figures is 123.5.
Scientific notation
Expressing a number in scientific notation makes significant digits explicit because the coefficient contains the intended precision.
Frequently asked questions
What are significant figures?
Significant figures are digits that communicate the precision of a measured or reported number. They include nonzero digits, zeros between significant digits and certain trailing zeros.
Are leading zeros significant?
No. Leading zeros before the first nonzero digit normally locate the decimal point and do not count as significant figures.
Are trailing zeros significant?
Trailing zeros after a decimal point are significant. Trailing zeros in a whole number without an explicit decimal or scientific notation can be ambiguous.
How do I round to significant figures?
Locate the last digit that should remain significant, inspect the next digit and apply ordinary rounding at that place value.
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