What this calculator does
Percent error works out how far a measured or estimated value is from the accepted true value. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaPercent error = |measured − accepted| / |accepted| × 100
The inputs explained
| Field | What to enter |
|---|---|
| Measured value | A number. Starts at 9.8. |
| Accepted (true) value | A number. Starts at 10. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with measured value
Every other input is held at the calculator’s starting values while measured value varies. Select any row to load that scenario into the calculator.