Pressure Gauge Accuracy Calculator
Pressure gauges and many transmitters specify accuracy as a percentage of full scale. See the allowable error in pressure units and how large it is relative to your actual reading.
- Error = class % × full scale = 1 % × 16 = ± 0.16
- Relative to the reading: 0.16 ÷ 4 = 4 %
Error as % of reading across the scale
| Reading (% of FS) | Reading | Error (% of reading) |
|---|---|---|
| 10 % | 1.6 | ± 10 % |
| 25 % | 4 | ± 4 % |
| 50 % | 8 | ± 2 % |
| 75 % | 12 | ± 1.333 % |
| 100 % | 16 | ± 1 % |
Accuracy Class Formula
Error % of reading = Maximum error ÷ Reading × 100
EN 837-1 accuracy classes define the permissible error as a percentage of the measuring span, constant across the whole scale.
Worked example
A class 1.0 gauge of 0 to 16 bar may be off by ± 0.16 bar anywhere on the scale. At a reading of 4 bar that is ± 4 % of the reading.
Frequently Asked Questions
What does class 1.6 mean on a pressure gauge?
The error may be up to 1.6 % of the full scale value at any point on the dial.
Is % of full scale the same as % of span?
For gauges starting at zero, yes. For compound or offset ranges, span is the difference between the end values.
Which class is used for test gauges?
Test and reference gauges are typically class 0.1, 0.25 or 0.6; process gauges are class 1.0 to 2.5.
Learn more on the blog
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