What is the percent error formula?

% Error = |Experimental - Theoretical| / |Theoretical| × 100. The absolute value bars mean we ignore the sign — we're only interested in how far off we are.

What is a good percent error?

In most lab settings, less than 5% error is acceptable. Less than 1% is excellent. Greater than 10% often indicates a procedural error or measurement issue.

Percent Error Calculator

Quick answer: Enter experimental and theoretical values to calculate percent error, absolute error, and relative error.

Percent error measures how far an experimental result is from the expected (theoretical) value. Used in science labs, engineering, and quality control to evaluate measurement accuracy.

Last reviewed: April 2026Report an error

Experimental Value

Theoretical Value

Percent Error

2.00%

Percent error: 2.00%, absolute error: 0.1999999999999993.

Percent Error

2.00%

Absolute Error

0.1999999999999993

Relative Error

0.0200

How to Use This Percent Error Calculator

1Enter your experimental (measured) value.
2Enter the theoretical (accepted) value.
3Read percent error, absolute error, and relative error.

Frequently Asked Questions

: % Error = |Experimental - Theoretical| / |Theoretical| × 100. The absolute value bars mean we ignore the sign — we're only interested in how far off we are.
: In most lab settings, less than 5% error is acceptable. Less than 1% is excellent. Greater than 10% often indicates a procedural error or measurement issue.

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Percent Error Calculator

How to Use This Percent Error Calculator

Frequently Asked Questions

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