Percentage error calculator.

Percentage error measures how far an experimental or estimated value is from the true (accepted) value, expressed as a percentage of the true value.

% Error = |Experimental − Theoretical| ÷ |Theoretical| × 100. The absolute values ensure the result is always positive.

A low percentage error means your measured or estimated value is very close to the true value — high accuracy.

Yes, if your experimental value exactly matches the theoretical value, the percentage error is 0%.

The formula is undefined when the theoretical value is zero (division by zero). In practice, use an alternative error metric like absolute error.

Yes — by convention, percentage error uses absolute values so the result is always ≥ 0%.