Math Guide

Percentage Error โ€” How to Calculate Accuracy in Measurements

CalcHub Pro  ยท  April 2026  ยท  5 min read

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Overview

Percentage error tells you how accurate a measurement or estimate is compared to the true value. Used extensively in science, engineering, and quality control.

The Formula

Percentage Error = |Measured โˆ’ True| รท True ร— 100

Standard formula used by professionals worldwide

Worked Example

Step-by-step

Measured 97cm, true value 100cm โ†’ error = |97โˆ’100|รท100ร—100 = 3%

Key Points

Frequently Asked Questions

What is acceptable percentage error?

Depends on context. Medical devices: <1%. Construction: 1-5%. Estimation: 5-10%.

Difference between percentage error and percentage difference?

Error compares to known true value. Difference compares two measurements without knowing truth.

How to reduce measurement error?

Multiple measurements and averaging. Better equipment. Controlled conditions.

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