Significant Figures Calculator
Count significant figures, round to specified precision, and perform arithmetic operations following proper sig fig rules. Essential for chemistry, physics, and scientific calculations.
Understanding Significant Figures
What Are Significant Figures?
Significant figures (sig figs) are the meaningful digits in a number that contribute to its precision. They indicate the reliability of a measurement and help maintain proper precision in calculations.
Counting Rules
- Non-zero digits are always significant (e.g., 123 has 3 sig figs)
- Zeros between non-zero digits are significant (e.g., 1002 has 4 sig figs)
- Leading zeros are NOT significant (e.g., 0.0045 has 2 sig figs)
- Trailing zeros after decimal are significant (e.g., 12.00 has 4 sig figs)
- Trailing zeros without decimal are ambiguous (e.g., 1200 has 2-4 sig figs)
Arithmetic Rules
Addition/Subtraction: Result should have same number of decimal places as the number with fewest decimal places. Multiplication/Division: Result should have same number of sig figs as the number with fewest sig figs.
When to Use This Calculator
- Chemistry lab calculations and stoichiometry
- Physics measurements and error analysis
- Engineering calculations requiring precision tracking
- Scientific notation and data reporting
Common Mistakes
- Counting leading zeros as significant (0.0045 has 2, not 4)
- Using multiplication rule for addition (different rules!)
- Not tracking significant figures throughout multi-step calculations
Educational Purpose Disclaimer
This calculator is provided for educational purposes only. Results should not be used as the sole basis for critical decisions. Always verify important calculations independently and consult qualified professionals when needed.