Percent Error Calculator
Math ToolsHow far an experimental value is from the true value
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History
All history →Percent Error Calculator — at a glance
Check how accurate a measurement is.
Measured 9.6
True 9.81
Calculate Error
Percent error
How to use it — step by step
The measured value and the accepted (true) value.
1
Enter your values
Fill in the fields. Default numbers are shown so you can see how it works.
2
Press Calculate Error
The answer appears at once as large result cards.
3
Copy or share
Copy the result, or share a link that opens with your numbers filled in.
Pro tips
Small things that make the result better.
✦Percent error = |measured − true| ÷ |true| × 100.
✦The true value cannot be zero.
✦A lower percent means a more accurate result.
Quick facts
Freeno signup
Privateruns in your browser
Instantresult in a second
No limituse it as often as you like
Frequently Asked Questions
Can percent error be negative?+
The usual formula uses the absolute value, so it is positive. The sign of the error is shown separately.
What is a good percent error?+
Under 5% is fine for many school experiments.
Is my data safe?+
Yes. Everything runs inside your own browser. Your text, files and images are never uploaded to any server.
Is this tool really free?+
Yes — completely free, no signup, no watermark and no usage limit.
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