What does percent error tell you?

Percent error tells you how far off a measured or estimated value is from the true (accepted) value, expressed as a percentage of the true value. A lower percent error means a more accurate measurement.

Why do we use the absolute value in the percent error formula?

The absolute value ensures the result is always a positive number, representing only the magnitude of the error. Whether you measured too high or too low, the error percentage tells you how inaccurate the measurement was.

What is considered a good percent error?

It depends on the field. In high-precision physics experiments, less than 1% is expected. In general chemistry labs, under 5% is typically acceptable. In social sciences or engineering estimates, up to 10% may be reasonable.

How is percent error different from percent difference?

Percent error compares a measured value to a known true value. Percent difference compares two measured values with no known 'correct' answer, using their average as the base instead of a theoretical value.

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IPL 2026

Percent Error Calculator

Find the percent error between a measured value and its exact theoretical value.

Complete User Guide

Enter your measured (experimental) value and the accepted (theoretical) value. The calculator finds the absolute difference, divides it by the theoretical value, and multiplies by 100 to express the error as a percentage.

The Mathematical Formula

|(Approx - Exact) / Exact| * 100

Percent Error = |Experimental − Theoretical| / |Theoretical| × 100. The absolute value bars ensure the result is always positive, representing the magnitude of error regardless of direction.

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