Relative error = absolute error ÷ true value
Relative error = |approximate value – true value| ÷ |true value|
Multiply by 100 to get percentage error
Percentage error = relative error × 100%
Use the true or accepted value as the denominator
Keep the result unitless
Example: if true value = 50 and measured value = 47, relative error = |47 – 50| ÷ 50 = 3 ÷ 50 = 0.06
Example: percentage error = 0.06 × 100% = 6%