What is the Error Percentage Calculator?
Calculate percent error, absolute error, relative error, and percent difference with this free error percentage calculator. Enter measured and accepted values — get step-by-step formulas, signed error direction, and accuracy for physics and chemistry lab reports. Runs instantly in your browser.
How to use the Error Percentage Calculator
- Choose Percent Error, Absolute Error, Relative Error, or Percent Difference mode.
- Enter the measured or experimental value and the accepted or theoretical reference.
- For percent difference, enter two comparable trial values.
- Review percent error, absolute error, relative error, and accuracy.
- Copy the full summary with calculation steps for your lab report.
Common use cases
- Calculating percent error for density or gravity lab experiments
- Finding absolute error between measured and handbook values
- Comparing relative error across different unit scales
- Computing percent difference between duplicate trials
- Checking homework answers for error analysis problems
Frequently asked questions
- What is percent error?
- Percent error measures how far a measured value deviates from an accepted (true or theoretical) value: percent error = |measured − accepted| / |accepted| × 100%.
- What is the difference between absolute and relative error?
- Absolute error is |measured − accepted| in the same units as the measurement. Relative error is absolute error divided by |accepted|, often expressed as a percentage.
- What is percent difference?
- Percent difference compares two experimental values without a known true value: |v₁ − v₂| / ((|v₁| + |v₂|) / 2) × 100%. It is used when comparing two trials or methods.
- What is accuracy in this calculator?
- Accuracy is reported as 100% − percent error. It indicates how close the measurement is to the accepted value as a percentage.
- Can the accepted value be zero?
- Percent and relative error require a non-zero accepted value. Absolute error and percent difference can still be computed when one value is zero, with appropriate interpretation.
