1. What is a PSI to PSIG Calculator?

Definition: This calculator converts absolute pressure (PSI) to gauge pressure (PSIG) by subtracting atmospheric pressure.

Purpose: It helps engineers, technicians, and students convert between absolute and gauge pressure measurements.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \text{PSIG} \) — Gauge pressure (pounds per square inch gauge)
• \( \text{PSI} \) — Absolute pressure (pounds per square inch absolute)
• \( 14.7 \) — Standard atmospheric pressure at sea level (psi)

Explanation: Gauge pressure is the pressure relative to atmospheric pressure, while absolute pressure includes atmospheric pressure.

3. Importance of PSI to PSIG Conversion

Details: Most pressure gauges measure relative to atmospheric pressure (PSIG), while many calculations require absolute pressure (PSI).

4. Using the Calculator

Tips: Enter the absolute pressure in PSI. The calculator will subtract 14.7 psi (standard atmospheric pressure) to give PSIG.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between PSI and PSIG?
A: PSI is absolute pressure (including atmospheric), while PSIG is gauge pressure (excluding atmospheric).

Q2: Why 14.7 psi for atmospheric pressure?
A: This is standard atmospheric pressure at sea level. Actual atmospheric pressure varies with altitude and weather.

Q3: Can PSIG be negative?
A: Yes, when absolute pressure is below atmospheric pressure (vacuum conditions).

Q4: When would I need this conversion?
A: When working with pressure vessel calculations, HVAC systems, or any application where gauge and absolute pressure must be distinguished.

Q5: How does altitude affect this conversion?
A: At higher altitudes, atmospheric pressure is less than 14.7 psi. For precise work, adjust the atmospheric pressure value accordingly.