Significant Figures Calculator
Result
Significant Figures in Calculations
When performing calculations with measured values, the result should reflect the precision of the least precise measurement. Different operations follow different rules:
Rules for Mathematical Operations:
Addition & Subtraction:
The result should have the same number of decimal places as the measurement with the fewest decimal places.
Example:
12.1 + 1.35 = 13.45 → 13.5
(12.1 has 1 decimal place)
Multiplication & Division:
The result should have the same number of significant figures as the measurement with the fewest significant figures.
Example:
12.1 × 1.35 = 16.335 → 16.3
(Both have 3 significant figures)
Common Examples:
| Calculation | Raw Result | Proper Result | Reason |
|---|---|---|---|
| 2.5 + 1.25 | 3.75 | 3.8 | 2.5 has 1 decimal place |
| 4.0 × 3.14 | 12.56 | 13 | 4.0 has 2 sig figs |
| 100 ÷ 3.0 | 33.333... | 33 | 3.0 has 2 sig figs |
| 12.50 - 0.1 | 12.4 | 12.4 | 0.1 has 1 decimal place |
Important: These rules help maintain the appropriate level of precision in scientific calculations and prevent false precision in results.