Percent Error Calculator
Quickly find your Percent error result with our free Percent Error Calculator. Simple, fast, and accurate.
Values
Percent error
What is a Percent Error Calculator?
The Percent Error Calculator helps you calculate the percent error between a measured value and a true or accepted value. Just enter your numbers and the tool does the rest — no manual math, no guesswork.
How to calculate Percent Error manually (the formula)
The specific formula depends on what you are calculating. The calculator applies the correct equation automatically, but understanding the formula helps you verify the results and adapt them to your own needs.
Example calculation
Enter your values into the calculator and it will produce an instant result. For a step-by-step walkthrough, try different inputs and observe how each one affects the outcome.
Common mistakes
- Forgetting to take the absolute value — Percent error is always positive. The sign indicates whether the measurement was high or low.
- Dividing by the measured value instead of the true value — Always divide by the accepted or true value, not the measured value.
- Confusing percent error with percent difference — Percent error uses a known standard. Percent difference compares two measurements without a standard.
Frequently asked questions
What is percent error?
Percent error measures how far a measured value is from the true value, expressed as a percentage of the true value.
How do I calculate percent error?
Subtract the true value from the measured value, take the absolute value, divide by the true value, and multiply by 100.
What is the percent error formula?
Percent Error = |Measured − True| ÷ |True| × 100. The result is always non-negative.
What does a negative percent error mean?
Percent error is reported as non-negative (absolute value). A negative raw difference means the measured value was lower than the true value.
What’s the difference between percent error and percent difference?
Percent error compares a measured value to an accepted true value. Percent difference compares two experimental values.
Can percent error be over 100%?
Yes. If the measured value is more than double the true value, the percent error exceeds 100%.