Calculator tool
Percent error measures how far an experimental (measured) value is from the theoretical (accepted) value, expressed as a percentage. Formula: |experimental − theoretical| / |theoretical| × 100.
Review the inputs carefully and treat the output as an estimate. For decisions involving money, taxes, health, law, or security, compare the result with trusted professional guidance when needed.
Why use absolute value in percent error?
Absolute value makes percent error always positive, showing magnitude without direction. Some fields use signed error to indicate over or under estimation.
What is a good percent error?
It depends on the field. In many lab sciences, less than 5% is considered acceptable. Precision instruments aim for much less.
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