Enter the true or accepted value and the observed value into the calculator to determine the percentage accuracy of the test or measurement.

## Percentage Accuracy Formula

The following formula is used to calculate the percentage accuracy of a test.

%A = 100 – | (Tv-Ov) / Tv *100 |

- Where %A is the percentage accuracy
- Tv is the true value or theoretical value
- Ov is the observed or measured value

## Percentage Accuracy Definition

A percentage accuracy is a measure of how close a measurement or test is to the true or theoretical value of that measurement or test. This is a ratio of the difference between true and measured divided by the true value.

## Percentage Accuracy Example

How to calculate a percentage accuracy?

**First, determine the true value.**Calculate the theoretical value the measurement or test should yield.

**Next, determine the observed value.**Determine the observed or actual measured value.

**Finally, calculate the percentage accuracy.**Calculate the accuracy using the formula above.

## What is a good accuracy percentage?

A good accuracy percentage depends on the test being performed, but the closer to 100% accuracy the better in all cases. For example, a percentage accuracy of a test for a chemical composition through mass spectrometer is expected to be 99+% accurate

## FAQ

**What is a percent accuracy?**

A percent accuracy is a ratio used to described how close a measured or observed value of a measurement or test is to the theoretical value.