Enter a number or expression into the Significant Figures Calculator, choose your operation type, and set how many sig figs to round to — you'll get the significant figures count, a rounded result, and the value expressed in scientific notation.
Significant Figures
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Original Number
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Rounded Result
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Scientific Notation
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Significant figures are the meaningful digits in a number that indicate the precision of a measurement or calculation. They include all non-zero digits, zeros between non-zero digits, and trailing zeros in decimal numbers.
The number 0.0098 has 2 significant figures. The leading zeros (0.00) are not significant as they only indicate the decimal place, while the digits 9 and 8 are significant.
The number 5000 is ambiguous - it could have 1, 2, 3, or 4 significant figures depending on how it was measured. To clarify, write it in scientific notation: 5×10³ (1 sig fig) or 5.000×10³ (4 sig figs).
To round to n significant figures: count n digits from the first non-zero digit, then round the last digit based on the following digit. If it's 5 or greater, round up; if less than 5, round down.
In multiplication and division, the result should have the same number of significant figures as the measurement with the fewest significant figures. For example: 5.45 × 2.1 = 11 (2 sig figs).
The number 100.00 has 5 significant figures. The decimal point indicates that all trailing zeros are significant, making all five digits (1, 0, 0, 0, 0) meaningful.
No, zeros are significant only in certain cases: zeros between non-zero digits are always significant, trailing zeros after a decimal point are significant, but leading zeros are never significant.
In scientific notation (like 3.45×10⁵), only the digits in the coefficient (3.45) count as significant figures. The exponent doesn't affect the count, so this number has 3 significant figures.