Percent Error Calculator
Calculate the percent error between experimental and theoretical values. Essential for scientific experiments, data analysis, and quality control measurements.
Enter Values
Display Settings
Quick Examples
Results
How Percent Error Works
Understanding Percent Error
Percent error measures the accuracy of an experimental or measured value compared to a known theoretical or accepted value.
The formula is: |Experimental - Theoretical| / |Theoretical| × 100%
A lower percent error indicates higher accuracy, while a higher percent error suggests less precision in the measurement.
Types of Error Calculations
Applications of Percent Error
Scientific Research
Quality Control
Business & Finance
Example Calculations
Laboratory Measurement
A student measures the density of water as 0.98 g/mL. The theoretical value is 1.00 g/mL.
Temperature Reading
A thermometer reads 24.5°C when the actual temperature is 25.0°C.
Sales Forecast
A company forecasted $100,000 in sales but actually achieved $95,000.
Frequently Asked Questions
What's the difference between percent error and percent difference?
Percent error compares an experimental value to a known theoretical value, while percent difference compares two measured values without assuming one is "correct."
Can percent error be negative?
No, percent error is always positive because it uses absolute values. If you need to know the direction of error, use relative error or percent change instead.
What's considered a good percent error?
This depends on the context. In laboratory settings, less than 5% is often considered good, less than 1% is excellent. For business forecasting, less than 10% might be acceptable.
What if the theoretical value is zero?
Percent error cannot be calculated when the theoretical value is zero because it would involve division by zero. Use absolute error instead.