Significant Figures Calculator
Last updated: October 15, 2026
Round a number to a chosen number of significant figures and show scientific notation.
Rounded number
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- Scientific notation: —
- Order of magnitude: —
- Absolute rounding difference: —
On this page
Quick summary: Round a number to a chosen number of significant figures and show scientific notation.
Read the method, example and limitations
Updated reference sections in this guide are in English.
Guide language: English. Updated October 15, 2026.
What this calculator estimates
Round a number to a chosen number of significant figures and show scientific notation.
Inputs and units
Enter Number, Significant figures. Use the units shown. Required fields cannot be blank. Use zero only where that field and the model allow it. Select Calculate after changing the values.
Method and assumptions
Round the numerical input to 1 to 15 chosen significant figures, retaining meaningful trailing zeros in the result string. The rounded value is also shown in normalized scientific notation with its exponent and absolute rounding difference.
Worked example
0.00456789 to three significant figures becomes 0.00457. A value of 1e-100 to three significant figures displays as 1.00e-100 rather than failing because it needs more than 100 decimal places.
Limitations
This tool applies decimal rounding to a floating-point input. It does not infer laboratory uncertainty or the precision of a number merely from how it was originally typed.