Percent Error Calculator
Calculate the percent error between your experimental value and the theoretical (accepted) value. Find measurement accuracy and direction of error. Free.
Percent Error Calculator
toolznova.com • Free Calculator
How to Use
Calculate percent error in 3 steps.
Enter Experimental
Enter the value you measured in your experiment.
Enter Theoretical
Enter the accepted or theoretical true value.
Get Error %
Click Calculate for percent error, absolute error, and direction.
Why ToolzNova?
Instant
Results in milliseconds.
Accurate
Precise formulas every time.
Private
No data sent anywhere.
Everywhere
Mobile, tablet, desktop.
Why Calculate Percent Error?
- Lab Reports: Required metric in all science lab reports.
- Accuracy Check: Measure how accurate your experimental results are.
- Calibration: Verify instrument calibration against known standards.
- Quality Control: Check if measured values are within acceptable tolerances.
- Science Class: Essential calculation for physics, chemistry, and biology labs.
- Engineering: Compare simulated vs actual performance metrics.
Tips & Examples
- Lower percent error = more accurate result. Aim for <5% in most labs.
- Percent error uses absolute value — sign shows over/underestimate.
- If experimental = theoretical exactly, percent error = 0%.
- Formula: |Experimental - Theoretical| / |Theoretical| × 100.
- In physics labs, g = 9.81 m/s². If you measure 9.65, error = 1.63%.
- Always report percent error with the direction (over or underestimate).
Free Percent Error Calculator Online
ToolzNova's free percent error calculator computes the percentage difference between your experimental measurement and the accepted theoretical value. Shows absolute error and whether your result is an overestimate or underestimate.
Percent error is the standard way to quantify accuracy in science experiments. It expresses the error as a percentage of the theoretical value, making it easy to compare accuracy across different experiments and measurements.
Percent Error Formula
Percent Error = |Experimental − Theoretical| / |Theoretical| × 100%. The absolute value ensures the result is always positive. The direction (over/under) is determined separately by comparing experimental to theoretical.