Absolute Pressure Calibration Helper

Use current atmospheric pressure and indicated gauge pressure to calculate absolute pressure targets for transmitter calibration.

Atmospheric Pressure

Current local barometric pressure
Zero Point (inH₂O absolute)
406.77
Zero Point (PSIA)
14.696

PSI Input and Output

Gauge pressure from calibrator, can be negative for vacuum
Output from PSI Input (PSIA)
65.296
Output from PSI Input (inH₂O absolute)
1807.53

inH₂O Input and Output

Optional alternate entry for low pressure work
Output from inH₂O Input (inH₂O absolute)
442.97
Output from inH₂O Input (PSIA)
15.998
PSIA = atmospheric PSI + indicated PSIG
inH₂O absolute = atmospheric inH₂O + indicated inH₂O gauge
How to use:
Enter current atmospheric pressure in inHg. The tool calculates the transmitter zero point in both PSIA and inH₂O absolute. Then enter the calibrator indicated gauge pressure in either psi or inH₂O. The tool adds that indicated gauge pressure to atmospheric pressure to show the true absolute pressure value to enter as the actual calibration point in the transmitter.

This also works for vacuum. If the calibrator shows a negative gauge value, the tool subtracts that amount from atmospheric pressure to show the corresponding PSIA or inH₂O absolute low point.