Relative Error Calculator
Calculate the relative error between measured and actual values.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
Can't find what you need?
Request a ToolHow to Use the Relative Error Calculator
Enter the measured value and the true (actual) value. The calculator computes the relative error as |measured - actual| / |actual|, and also shows the absolute error and percent error.
About This Calculator
Relative error expresses measurement accuracy as a fraction of the true value. Unlike absolute error, it scales with the magnitude being measured, making it useful for comparing accuracy across different quantities. A relative error of 0.02 means the measurement is off by 2% of the true value.
Frequently Asked Questions
What is the difference between relative and absolute error?
Absolute error is |measured - actual|, a fixed number. Relative error divides by the actual value, giving a dimensionless ratio that is easier to compare across different scales.
When is relative error more useful than absolute error?
When comparing measurements of different magnitudes. An error of 1 gram is significant when measuring 10 grams (10% relative error) but negligible when measuring 1000 grams (0.1%).
Can relative error exceed 1?
Yes. A relative error greater than 1 means the measurement is off by more than 100% of the true value.