Percent Error Calculator

True Value:

Observed Value:

Percent Error

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

  1. Observed Value = 2.50 g/cm³
  2. 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 %

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