Significant Figures Calculator
Round a number to a chosen number of significant figures.
Precision, properly rounded
Significant figures capture how precise a number really is, counting from its first non-zero digit. Rounding to a set number of them is standard practice in science and engineering.
Pi to three significant figures is 3.14; to five, 3.1416. This tool rounds any number to the precision you choose and shows the scientific-notation form for very large or small values.
Precise and private
The calculation runs in your browser, so nothing you enter is uploaded.
Frequently Asked Questions
What are significant figures?
The digits that carry meaning in a number’s precision, starting from the first non-zero digit.
How does rounding work?
The tool keeps the chosen number of significant digits and rounds the rest, using scientific notation when needed.
Why does precision matter?
In science and engineering, reporting too many digits implies false precision, so results are rounded to significant figures.
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