Percent Error Calculator

Calculate the percentage error, absolute error, and relative error between an observed value and an accepted value with step-by-step explanations.

Calculate Percent Error

Enter the experimental (observed) value and the accepted (true) value below.

Experimental / Observed Value ($E$):

Accepted / True Value ($A$):

How to Calculate Percent Error

Percent error calculates the relative difference between an experimental (observed) measurement and a known theoretical or accepted value.

Formula:

$$\text{Percent Error} = \left| \frac{\text{Experimental Value} - \text{Accepted Value}}{\text{Accepted Value}} \right| \times 100\%$$

Frequently Asked Questions (FAQs)

Percent error is a measure of how inaccurate a measurement is, expressed as a percentage of the true or accepted value.

Standard scientific convention uses absolute values, making percent error always positive or zero. However, in some contexts where direction matters, the absolute sign is omitted to show underestimation or overestimation.

Absolute Error is the raw difference between observed and accepted values ($|E - A|$). Relative Error scales this difference by dividing it by the accepted value ($|E - A| / |A|$).