MATH / CALCULATOR

Percent Error Calculator.

Compare a measured value with an accepted value and see the error.

LET’S WORK IT OUT

Your numbers, your answer.

≈

THE WHY BEHIND THE ANSWER

How it works.

Percent error describes the size of the difference relative to a known reference. First subtract the accepted value from the measured value, then take the absolute difference, divide by the absolute accepted value and multiply by 100.

THE FORMULAPercent error = |measured − accepted| ÷ |accepted| × 100

Worked example

A measured value of 9.6 compared with an accepted value of 10 has an absolute error of 0.4 and a percent error of 4%.

Good to know

Use matching units before calculating. Percent error compares a result against a reference; it does not measure uncertainty or prove that a result is accurate.

ONE MORE THING

Why can the accepted value not be zero?

Relative and percentage error divide by the accepted value. Division by zero is undefined; use the absolute difference instead.