Percent Error Formula
The percent error formula helps us to calculate the exact amount of error that occurred in measuring the dimension or other quantities. The percent error formula is applicable to a wide range of scenarios, one might come across on a daily basis. In this section, we will learn about the percent error formula, and how to use it.
What is the Percent Error Formula?
Let's learn the formula, after which you will be in a great position to solve problems on this topic. Percentage or percent error formula of a given measurement can be expressed using the following expression.
Percent Error = (Experimental Value  Theoretical value) / Theoritical value × 100

Example 1: The radius of a nut is measured as 0.5in. The actual value of the radius of the nut was known to be 0.47in. Find the percent error in the measurement.
Solution: To find: Percent Error in the measurement.
Theoritical value = 0.47in, Experimental Value = 0.5in (given)
Using Percent Error Formula,
Percent Error = (Experimental Value  Theoretical value) / Theoritical value × 100Putting the values,
Percent Error = {(0.5 0.47) / 0.47} ×100
Percent Error = {(0.5 0.47) / 0.47} ×100
Percent Error = 0.06 ×100
Percent Error = 6Answer: The percent error in the measurement is 6%.

Example 2: The price of a car was estimated to be $12995. The actual price of the car was $13000. Find the percentage error in the estimation using the percent error formula.
Solution:
To find: Percentage error in the estimation.
Theoritical value = $13000, Experimental Value = $12995 (given)
Using Percent Error Formula,
Percent Error = (Experimental Value  Theoretical value) / Theoritical value ×100Putting the values,
Percent Error = {(12995 13000) / 13000} ×100
Percent Error = {(5) /13000} × 100
Percent Error = 0.00038461 × 100
Percent Error = 0.03Answer: The percent error in the estimation is 0.03%.