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Percent Error Calculator

Percent error tells you how far a measured or experimental value is from the accepted true value, expressed as a percentage. It is calculated as the absolute difference between the measured value and the true value, divided by the absolute true value, then multiplied by one hundred. This calculator returns the absolute error and the percent error so you can report the accuracy of an experiment or instrument. Percent error is a standard part of physics and chemistry lab reports because it quantifies how good a result is rather than just stating the raw numbers, and a smaller percent error means a more accurate measurement. Enter your measured value and the known true value and the tool computes both errors instantly. Everything runs locally in your browser, so your data never leaves the page.

How to use Percent Error Calculator

  1. Enter the true or accepted value.
  2. Enter your measured or experimental value.
  3. Read the absolute error and the percent error.

Frequently asked questions

What is the percent error formula?

Percent error equals the absolute difference between the measured and true value, divided by the true value, times 100 percent.

What does the absolute error show?

Absolute error is the raw difference between the measured value and the true value, before dividing by the true value.

Can percent error be negative?

The standard percent error uses the absolute difference, so it is reported as a positive percentage regardless of direction.

What is Percent Error Calculator?

Percent error tells you how far a measured or experimental value is from the accepted true value, expressed as a percentage. It is calculated as the absolute difference between the measured value and the true value, divided by the absolute true value, then multiplied by one hundred.

Is Percent Error Calculator free to use?

Yes. Percent Error Calculator is completely free, with no sign-up and no usage limits.

Does Percent Error Calculator work in a web browser?

Yes. Percent Error Calculator runs in any modern web browser. There is nothing to download or install.

Is my data private with Percent Error Calculator?

Yes. Percent Error Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.