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Significant Figures Calculator

Count, round, and work with significant figures. Essential for scientific calculations and precision measurement.

Enter Number
Provide the number to analyze

Enter any number, including decimals and scientific notation

Significant Figures Results
Analysis of your number

Enter a number and click "Calculate" to see your results

Significant Figures Rules
Key rules for identifying significant figures

Counting Rules

Non-zero digits: Always significant (1, 2, 3, 4, 5, 6, 7, 8, 9)
Zeros between non-zeros: Always significant (101, 2005)
Leading zeros: Never significant (0.045, 0.00012)
Trailing zeros: Significant only with decimal point (12.00, 0.450)

Examples

123.455 sig figs
0.004563 sig figs
100.04 sig figs
1.230 × 10³4 sig figs
About Significant Figures

What are Significant Figures?

Significant figures (also known as significant digits) are the digits in a number that carry meaning contributing to its precision. This includes all digits except:

  • Leading zeros (zeros before non-zero digits)
  • Trailing zeros when they are merely placeholders to indicate the scale of the number
  • Spurious digits introduced by calculations

Why Significant Figures Matter

  • Scientific Accuracy: Ensures that calculations reflect the precision of measurements
  • Error Prevention: Prevents false precision in calculations
  • Communication: Clearly communicates the uncertainty in measurements
  • Standardization: Provides a consistent way to express precision across scientific fields

Rounding Rules

General Rounding Rules:

  • • If the digit to be removed is less than 5, round down
  • • If the digit to be removed is 5 or greater, round up
  • • When rounding to significant figures, look at the first non-significant digit
  • • In scientific contexts, special rules apply for exactly 5 (round to even)

Applications

  • Chemistry: Calculating molar masses, concentrations, and reaction yields
  • Physics: Measuring physical constants and experimental results
  • Engineering: Specifying tolerances and precision in manufacturing
  • Medicine: Dosage calculations and laboratory results
  • Finance: Financial calculations requiring precision

Tips for Using This Calculator

  • Enter numbers in decimal format (e.g., 123.45) or scientific notation (e.g., 1.2345e2)
  • The calculator automatically identifies significant figures according to standard rules
  • Use the rounding function to express numbers with specific precision
  • Scientific notation helps clarify significant figures in very large or small numbers
  • Remember that trailing zeros after a decimal point are always significant