SuperCalX

Accuracy Calculator

Calculate the accuracy and percent error of a measurement.
Calculator
Enter your values
Analysis
Interpretation of the current calculator output

Enter values to see detailed analysis and insights.

How to Use

Step-by-step instructions
  1. 1Enter the observed (measured) value.
  2. 2Enter the actual (true) value.
  3. 3The calculator will display the accuracy percentage and the percent error.

Accuracy Formula

Accuracy measures how close a measured value is to the true or accepted value. It is the complement of the percent error.
Accuracy % = 100% - |(Observed - Actual) / Actual| x 100%

Variables:

ObservedThe measured or experimental value
ActualThe true or theoretical value

Example

Lab Experiment

Inputs:

Observed:9.8
Actual:10.0

Steps:

  1. 1.Error: |9.8 - 10.0| / 10.0 = 0.2 / 10.0 = 0.02
  2. 2.Percent Error: 0.02 x 100 = 2%
  3. 3.Accuracy: 100% - 2% = 98%
Result:
98%

Frequently Asked Questions

Can accuracy be negative?

Technically, if the error is greater than 100%, the formula would yield a negative accuracy, indicating a very poor measurement. However, accuracy is often treated as a magnitude or capped at 0% in some contexts.