Math Tools
Percentage Error Calculator
Calculate the percentage error between your measured (experimental) value and the true (theoretical) value. Essential for science labs and physics.
Percentage Error
0%
Absolute Error
0
Relative Error
0
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Percentage Error Formula
Percentage Error = |( Measured Value − True Value ) / True Value| × 100%
The absolute value ensures the result is always positive, showing the magnitude of the error regardless of direction. It is a standard metric in all scientific disciplines for evaluating the accuracy of measurements.
- 0% error: Perfect measurement — rarely achievable in practice.
- < 5% error: Generally considered acceptable in most school and college lab reports.
- > 10% error: Indicates significant measurement inaccuracy or a systematic error in the experiment.
🔬 Example: Chemistry Lab
If you measured the boiling point of ethanol as 78.9°C while the true value is 78.37°C: Error = |78.9 − 78.37| / 78.37 × 100 = 0.68%. Excellent precision!
Frequently Asked Questions
Percentage error analyzes the precision of your results by measuring how far off your experimental (measured) value is from the theoretically proven (true) value in a clinical layout.
The absolute equation is: |(Measured Value - True Value)| / True Value * 100. The absolute value bars guarantee that the error percentage is always represented as a positive scalar.
While 0% represents absolute physical perfection, minor fractional errors are expected in real-world physics and chemistry due to instrument calibration limits, environmental variables, and human response time.