What this tool answers
Choose the precision first, then round the value to that number of significant figures. This answers a different question from counting how many significant digits a measurement already contains.
Formula
Locate the first nonzero digit, retain N significant digits, and round using the next digit.
Worked example: Three-significant-figure reporting
Rounding 98,765.4 to three significant figures gives 98,800, conveniently written as 9.88 × 10⁴. This is a rounding operation, not a claim about how precisely the original quantity was measured.
Load these worked-example inputs
Limitations
Binary floating-point limits can matter near rounding boundaries. Use explicit decimal notation and an appropriate precision for the intended report.
Frequently asked questions
Why does rounding 98765.4 to three figures produce 98800?
The first three digits are 987 and the next digit is 6, so the retained portion rounds upward.
Are significant figures the same as decimal places?
No. Significant figures begin with the first nonzero digit; decimal places count positions after the decimal point.
Can rounding create measured accuracy?
No. It changes presentation, not the quality of the underlying measurement.