Psig to Psia
### Thermodynamics & Pressure Reference Standards (ASME & ASHRAE) Pressure measurement requires understanding the reference baseline: - **Gauge Pressure (PSIG)**: Measures pressure relative to local.
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📊 Results
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<iframe src="https://calcusolve.com/converter/psig-to-psia?embed=true" width="100%" height="600" frameborder="0" loading="lazy" title="Psig to Psia"></iframe> ⚖ Scenario Comparison
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📐 Formula
💡 Practical Example
An HVAC technician reading 118.0 psig on an R-410A manifold gauge uses 132.7 psia in thermodynamic saturation tables to determine a 40°F evaporating temperature.
📖 About Psig to Psia
Thermodynamics & Pressure Reference Standards (ASME & ASHRAE)
Pressure measurement requires understanding the reference baseline:
- Gauge Pressure (PSIG): Measures pressure relative to local ambient atmospheric pressure. A gauge reading zero at sea level is exposed to atmospheric air.
- Absolute Pressure (PSIA): Measures pressure relative to a perfect vacuum.
Governing Equations
PSIA = PSIG + P_atm
PSIG = PSIA - P_atm
Barometric Pressure by Altitude
- Sea Level (0 ft): P_atm = 14.696 psia = 29.92 inHg = 101.325 kPa
- 1,000 ft (305 m): P_atm = 14.175 psia = 28.86 inHg
- 3,000 ft (914 m): P_atm = 13.166 psia = 26.81 inHg
- 5,280 ft (Denver, CO): P_atm = 12.162 psia = 24.75 inHg
- 8,000 ft (2,438 m): P_atm = 10.916 psia = 22.22 inHg
How to Use This Calculator
Enter your Pressure Value to Convert (e.g. 118.0), Atmospheric Baseline & Elevation — choose from Sea Level (14.696 psia / 29.92 inHg / 1.000 atm), 1,000 ft Elevation (14.18 psia / 28.86 inHg), 3,000 ft Elevation (13.17 psia / 26.81 inHg), HVAC-R & Industrial Preset — choose from Custom Pressure Value, 0.0 psig (14.7 psia / Ambient Atmosphere), 32.0 psig (46.7 psia / Car Tire Gauge), and Conversion Direction — choose from PSIG to PSIA (Gauge to Absolute / Add Patm), PSIA to PSIG (Absolute to Gauge / Subtract Patm). Results update instantly as you type — adjust any value to compare scenarios.
The Formula
Conversion factors (to SI base unit or reference unit):
patm: 14.6959488
psia: 14.6959488
psig: 32.0
Worked Example
An HVAC technician reading 118.0 psig on an R-410A manifold gauge uses 132.7 psia in thermodynamic saturation tables to determine a 40°F evaporating temperature.
Understanding Your Result
Unit conversion precision: round to the same number of significant figures as your original measurement. Converting 6 feet to meters gives 1.8288 m — but if your measurement was approximate (±1 inch), expressing more than 2 decimal places is false precision. For international trade and technical specifications, SI units (meters, kilograms, liters) are the standard. US customary units (feet, pounds, gallons) differ from Imperial UK units: 1 US gallon = 3.785 L vs. 1 UK gallon = 4.546 L.
💡 Methodological Standards & Calculation Accuracy
- All calculations are performed client-side in your browser using verified, standards-compliant mathematical algorithms.
- Results are provided for educational and informational analysis; verify critical applications with certified domain specialists.
- Ensure input values are entered in consistent units matching the selector options to guarantee accurate outputs.
- Periodic recalibration is recommended whenever baseline assumptions, operating parameters, or external conditions change.
Results are for informational and educational purposes only. Always verify critical decisions with a qualified professional.