Percent Error Calculator
Calculate the percent error between an estimated or measured value and the true actual value. Widely used in science, engineering, and maths to assess the accuracy of measurements and predictions.
How It Works
Percent error measures how far off an estimated or experimental value is from the true accepted value, expressed as a percentage. A lower percent error means a more accurate result. The absolute value is used so the result is always positive regardless of whether the estimate was too high or too low.
The Formula
Percent Error = (|Estimated - Actual| / |Actual|) x 100
When to Use This
Percent error is commonly used in school and university science experiments to compare a measured result with the theoretical or accepted value. It also appears in forecasting, quality control, and any situation where you need to quantify how accurate an estimate was.
Worked Examples
Example 1: Estimated 9.8, actual 10
|9.8 - 10| = 0.2. 0.2 / 10 = 0.02. 0.02 x 100 = 2%
Example 2: Estimated 52, actual 50
|52 - 50| = 2. 2 / 50 = 0.04. 0.04 x 100 = 4%
Example 3: Estimated 95, actual 100
|95 - 100| = 5. 5 / 100 = 0.05. 0.05 x 100 = 5%
Example 4: Estimated 1.85, actual 2.0
|1.85 - 2.0| = 0.15. 0.15 / 2.0 = 0.075. 0.075 x 100 = 7.5%
Example 5: Estimated 112, actual 120
|112 - 120| = 8. 8 / 120 = 0.0667. 0.0667 x 100 = 6.67%
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