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Significant Figures Calculator

Round numbers to significant figures. Count sig figs and perform calculations.

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How to Use

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  1. Enter the number you want to analyze
  2. Optionally, enter the number of significant figures to round to
  3. Click "Analyze" to see the results
  4. View the digit breakdown and applied rules
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What is Significant Figures Calculator?

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Significant figures (sig figs) are the digits in a number that carry meaningful information about its precision. They are crucial in scientific measurements and calculations to express the accuracy of a measured quantity.

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Formula

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Rules for Significant Figures:

1. All non-zero digits are significant

2. Zeros between non-zero digits are significant

3. Leading zeros are NOT significant

4. Trailing zeros after a decimal point ARE significant

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Examples

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  • 0.00340 has 3 sig figs (3, 4, 0)
  • 5200 has 2 sig figs (ambiguous trailing zeros)
  • 3.14159 has 6 sig figs (all digits)
  • 1.00 has 3 sig figs (trailing zeros after decimal)
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FAQ

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Why are significant figures important?expand_more
Significant figures indicate the precision of a measurement. When performing calculations, the result should not be more precise than the least precise measurement used, which is determined by significant figures.
How do I round to significant figures?expand_more
Identify the significant digit at the position you're rounding to, look at the next digit: if it's 5 or greater, round up; if it's less than 5, round down. Then remove all digits after the rounding position.
Are trailing zeros without a decimal point significant?expand_more
This is ambiguous. For example, 5200 could have 2, 3, or 4 significant figures. To clarify, use scientific notation (5.2×10³ for 2 sig figs) or add a decimal point (5200. for 4 sig figs).