Accuracy is defined as the conformity of an indication to its true value. Accuracy is a percentage of the full range. For example, a gauge that has a scale of 0-300 psi with an accuracy of ±1% would mean that the gauge is accurate to within ± (plus or minus) 3 psi.
Accuracy Grade |
Lower 1/4 of scale |
Middle 1/2 of scale |
Upper 1/4 of scale |
4A | 0.1 | 0.1 | 0.1 |
3A | 0.25 | 0.25 | 0.25 |
2A | 0.5 | 0.5 | 0.5 |
1A | 1 | 1 | 1 |
A | 2 | 1 | 2 |
B | 3 | 2 | 3 |
C | 4 | 3 | 4 |
D | 5 | 5 | 5 |