Laboratory Formula
Percent Error Formula
Compares an experimental result with an accepted reference value.
Formula Summary
Percent Error
Compares an experimental result with an accepted reference value.
- Category
- Laboratory
- Equation
- % error = |experimental − accepted| ÷ |accepted| × 100
- Calculator
- Use Percent Error Calculator →
Equation
% error = |experimental − accepted| ÷ |accepted| × 100
Variables
- experimental = measured value
- accepted = reference value
How to Use This Formula
- Identify the known values from the problem statement.
- Convert all values into compatible units.
- Substitute the values into the equation and calculate the result.
- Check that the final answer has the correct unit and meaning.
Explanation
Percent error measures how far an experimental result differs from an accepted or theoretical value. It helps evaluate the accuracy of measurements and experiments.
Worked Example
If the accepted value is 50 and the experimental value is 48, the percent error is |48 − 50| ÷ 50 × 100 = 4%.
Common Mistakes
- Using the experimental value as the denominator.
- Ignoring the absolute value difference.
- Mixing accepted and measured values.
Applications
- Evaluating laboratory measurement accuracy.
- Analyzing experimental results.
- Comparing observed values with standards.
Related Formulas
Percent Difference
% difference = |A − B| ÷ ((|A| + |B|) ÷ 2) × 100
Compares two experimental values when neither is an accepted value.
Learn formula →Percent Yield
% yield = actual ÷ theoretical × 100
Compares the measured product yield with the theoretical yield.
Learn formula →Sample Standard Deviation
s = √(Σ(xᵢ − x̄)² ÷ (n − 1))
Measures the spread of sample observations around their mean.
Learn formula →