Calculyn

Significant Figures Calculator

Count significant figures in a number and round it to any number of sig figs.

Results update as you type.

Significant figures

4
Rounded to 2 sig figs
0.0046
Scientific notation
4.6e-3
Significant figures4

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Quick answer

0.004560 has 4 significant figures (4, 5, 6, and the trailing 0). Rounded to 2 sig figs it's 0.0046.

How it works

Non-zero digits always count. Zeros between digits count. Leading zeros never count. Trailing zeros count only when there's a decimal point.

Formula

Count digits from the first non-zero digit; trailing zeros count only with a decimal point.

Assumptions & limitations

  • Trailing zeros in whole numbers without a decimal point are not counted

Formula and assumptions reviewed October 2026 by the Calculyn team. How we build our calculators

Frequently asked questions

Does 1500 have 2 or 4 sig figs?

Without a decimal point it's treated as 2. Write 1500. or 1.500 × 10³ to show 4.