Laboratory Formula
Percent Difference Formula
Compares two experimental values when neither is an accepted value.
Formula Summary
Percent Difference
Compares two experimental values when neither is an accepted value.
- Category
- Laboratory
- Equation
- % difference = |A − B| ÷ ((|A| + |B|) ÷ 2) × 100
- Calculator
- Use Percent Difference Calculator →
Equation
% difference = |A − B| ÷ ((|A| + |B|) ÷ 2) × 100
Variables
- A = first value
- B = second 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 difference compares two measured values when there is no known accepted or theoretical value. It shows the relative difference between the two measurements.
Worked Example
If two measurements are 45 and 50, the percent difference is |45 − 50| ÷ ((45 + 50) ÷ 2) × 100 = 10.53%.
Common Mistakes
- Using an accepted value instead of the average of both values.
- Forgetting to calculate the absolute difference.
- Using inconsistent measurement units.
Applications
- Comparing repeated laboratory measurements.
- Evaluating agreement between experimental results.
- Analyzing measurement consistency.
Related Formulas
Percent Error
% error = |experimental − accepted| ÷ |accepted| × 100
Compares an experimental result with an accepted reference value.
Learn formula →Sample Standard Deviation
s = √(Σ(xᵢ − x̄)² ÷ (n − 1))
Measures the spread of sample observations around their mean.
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