Accuracy
The degree of closeness of a measured value or experimental result to the true or accepted reference value.
Governing formula
Error = |Measured - True| / True × 100%
SI unit
%
In depth
Accuracy reflects systematic bias in a measurement procedure or calibration. A measurement can be highly precise (repeatable) without being accurate if a systematic offset exists.
Examples in the real world
If accepted local gravity acceleration is 9.81 m/s², an experimental reading of 9.80 m/s² is highly accurate.