What is the Percent Error Calculator?
Calculate percent error between a measured (experimental) value and the true value. From percentages and fractions to logarithms and quadratic equations, these math calculators show exact results — using arbitrary-precision integers wherever whole-number answers can get very large.
How to use the Percent Error Calculator
- Enter your measured value, your true value.
- Results update automatically as you type; you can also press Calculate.
- Read the output: percent error, absolute error.
- Use the 📊 chart to see the result visually, then copy or share it.
Formula and method
Worked example
With measured value = 9.6, true value = 9.81, the Percent Error Calculator returns percent error: 2.1407%; absolute error: 0.21.
Tips for better results
- Use the formula section on each page to check your homework method, not just the answer.
- For very large factorials, combinations and base conversions we use exact big-integer math.
- Floating-point results are rounded to 12 significant digits to remove binary noise.
Frequently asked questions
What does the Percent Error Calculator do?
Calculate percent error between a measured (experimental) value and the true value.
How is it calculated?
The Percent Error Calculator uses this method: % error = |Measured − True| ÷ |True| × 100.
Can you show an example?
With measured value = 9.6, true value = 9.81, the Percent Error Calculator returns percent error: 2.1407%; absolute error: 0.21.
Is the Percent Error Calculator accurate?
Yes. It uses standard formulas and exact constants, and the results are verified by our automated test suite. Values are displayed to up to 12 significant digits.
Is this tool free and private?
Yes — the Percent Error Calculator is completely free with no sign-up, and it runs entirely in your browser, so the values you enter are never uploaded to our servers.
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