Free online percent error calculator -. 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.

## Math 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 %