Significant Figures Calculator

Count significant figures (sig figs) in a measurement, or round to a set number of them.

E notation works: 1.20e3.
Significant figures
Significant digits
Decimal places
Scientific notation
Rounded
Rule

Saved Calculations

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Significant Figure Rules

1. Nonzero digits always count. 2. Zeros between nonzero digits count (4,005 has 4). 3. Leading zeros never count (0.0045 has 2). 4. Trailing zeros count if there’s a decimal point (4.500 has 4). 5. Trailing zeros in a whole number with no decimal point are ambiguous (4,500 has 2, 3 or 4); write 4.50 × 10³ to be clear.

Worked Example

Tips

When multiplying or dividing, round the answer to the fewest significant figures among the inputs. When adding or subtracting, round to the fewest decimal places.