0.00450
3 significant figures: 4, 5 and the trailing 0 after the decimal point.
Significant Figures Calculator
Count the significant figures in a number and round it to any number of significant figures.
Type it exactly as written — trailing zeros and the decimal point matter.
Result
Significant figures
4
- Significant digits
- 4560
- Rounded to 2 figures
- 0.0046
Runs in your browser — nothing you enter is sent to a server.
How the Significant Figures Calculator works
Type a number exactly as it's written — trailing zeros and the decimal point change the answer — and the calculator counts its significant figures by the standard rules. It can also round the number to any number of significant figures.
- Non-zero digits are always significant.
- Zeros between non-zero digits are significant (1002 has 4).
- Leading zeros are never significant (0.00450 has 3).
- Trailing zeros count only with a decimal point (12.00 has 4; 1200 is ambiguous and counted as 2).
Formula
in a × 10n, every digit of a is significant
Examples
Rounding 0.0045678 to 3 figures
The result is 0.00457.
Frequently asked questions
How many significant figures does 1200 have?
It's ambiguous — 2, 3 or 4. Write 1200. (4) or 1.20 × 10³ (3) to be clear.
How many figures should an answer have?
For multiplication and division, as many as the least precise measurement you started with.
Do exact numbers count?
Counted items and defined values (12 in a dozen) have unlimited significant figures.
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