Percentage Error Calculator

Calculate percent error and absolute error between experimental measured and theoretical true values.

Overview

Calculates the percentage error and absolute error between experimental experimental measurements and accepted theoretical true values.

Formula & Calculation Method

Percentage Error (%) = (|Experimental Value - Theoretical Value| / |Theoretical Value|) × 100

Quantifies the experimental accuracy of laboratory measurements relative to known scientific benchmarks.

Worked Example: Gravitational Acceleration Lab Measurement

Inputs: Experimental Measured g = 9.62 m/s² | Accepted True g = 9.81 m/s²

  • Absolute error = |9.62 - 9.81| = |-0.19| = 0.19 m/s²
  • Relative error = 0.19 / 9.81 = 0.019368
  • Percentage error = 0.019368 × 100 = 1.94%

Summary: Experimental = 9.62 | True = 9.81 | Absolute Error = 0.19 | Percentage Error = 1.94%

Common Use Cases

  • Physics & Chemistry Labs: Compare experimental laboratory measurements against accepted standard physical constants.
  • Engineering Sensor Calibration: Quantify measurement drift and instrument error in temperature and pressure sensors.
  • Quality Assurance: Validate manufacturing assembly tolerances against theoretical CAD design specifications.

Frequently Asked Questions

What is an acceptable percentage error in science experiments?

In high school/introductory labs, under 5% to 10% is typical; in precision manufacturing and professional science, under 1% is required.

What is the difference between percent error and percent difference?

Percent error compares a measurement to an accepted true value; percent difference compares two experimental measurements when neither is considered the 'true' benchmark.

Why is the absolute value used in percent error?

Because percentage error measures the magnitude of inaccuracy, regardless of whether the measurement was too high or too low.

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