Free online percentage error calculator. Calculate percent error, absolute error, and relative error instantly. Compare experimental and theoretical values with step-by-step results. Pure client-side, no ads.
This percentage error calculator computes the difference between an experimental (measured) value and a theoretical (accepted) value, expressed as a percentage. It is widely used in science, engineering, and statistics to quantify measurement accuracy. All calculations are performed locally in your browser — no data is sent to any server.
Percentage error measures how inaccurate a measurement is, compared to the true or accepted value. It is calculated as: |Experimental - Theoretical| / |Theoretical| × 100%. A smaller percentage error indicates a more accurate measurement.
Absolute error is the simple difference between the experimental and theoretical values (|Experimental - Theoretical|). Relative error is the absolute error divided by the theoretical value, giving a dimensionless measure of accuracy. Percentage error is simply relative error expressed as a percentage.
No, percentage error is always expressed as a positive value (or zero) because we take the absolute value of the difference. This ensures the error represents the magnitude of inaccuracy regardless of direction.
That depends on the context. In many scientific experiments, errors below 5% are considered acceptable. For precision instruments, errors below 1% or even 0.1% may be expected. The acceptable range depends on your field and the precision of your measuring equipment.
Yes, completely free. No ads, no registration, no limits. All calculations happen in your browser.