Calculate Percent Error Easily – Our Free Percent Error Calculator helps you quickly determine the accuracy of your measurements. Simply input true values and observed values then click the calculate button
What is a Percent Error?
Percent error, also known as relative error, is a measure of the difference between two values (true values and observed values), expressed as a percentage of the accepted value.
Percent Error Formula
The formula for calculating percent error is:
Percent error = |True values – Observed value| / True value * 100
How to Calculate Percent Error?
Follow these steps to calculate the percent error:
Step 1 – Identify the observed value you obtained through your measurement, calculation, or experiment.
Step 2 – Determine the “True Value”: The true value is the accepted or expected value
Step 3 – Subtract the Observed Value from the True Value, |TV – OV|
Step 4 – Divide the absolute difference by the True Value
Step 5 – Multiply the result by 100%
Solved Example
Example – Let’s say you’re measuring the density of a substance, and the true value (accepted value) for the density is 2.70 g/cm³. After conducting your experiment, you find that the density is 2.50 g/cm³.
Used this formula – Percent error = |TV – OV| / TV * 100
Given values
- Observed Value = 2.50 g/cm³
- True Value = 2.70 g/cm³
Put this value in Formula
Percent error = |2.70 – 2.50| / 2.70 * 100 = 0.0741 * 100 = 7.41 %