Percent Error Calculator
Determine the precision of your measurements. This calculator helps you see how close your experimental data is to the known theoretical value.
What is percent error?
Percent error is a measure of how accurate a measurement or experimental value is compared to a known, theoretical, or accepted value. It is expressed as a percentage.
How do you calculate percent error?
The formula is: [ |Experimental Value - Theoretical Value| / |Theoretical Value| ] Ć 100. The absolute value bars ensure that the error is always a positive percentage.
What is a "good" percent error?
In many high school science labs, a percent error under 5% or 10% is considered very good. In professional scientific research, the acceptable error margin may be much smaller (e.g., less than 1%).
What is the difference between error and percent error?
Error is the simple difference between the values (Experimental - Theoretical). Percent error scales that difference relative to the size of the theoretical value, making it easier to compare accuracy across different experiments.