1. What is PSI to PSIG Conversion?

PSIG (Pounds per Square Inch Gauge) is the pressure reading relative to atmospheric pressure, while PSI (Pounds per Square Inch) is absolute pressure. The conversion accounts for standard atmospheric pressure (14.7 psi at sea level).

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• \( PSI \) — Absolute pressure in pounds per square inch
• \( 14.7 \) — Standard atmospheric pressure at sea level (psi)

Explanation: Gauge pressure (PSIG) is always the absolute pressure (PSI) minus atmospheric pressure.

3. Importance of PSIG Calculation

Details: Most pressure gauges read in PSIG (relative to atmospheric pressure), making this conversion essential for engineering, HVAC, and industrial applications where absolute pressure is needed.

4. Using the Calculator

Tips: Enter PSI value (must be greater than 0). The calculator will automatically subtract atmospheric pressure (14.7 psi) to give you PSIG.

5. Frequently Asked Questions (FAQ)

Q1: Why subtract 14.7 psi?
A: This accounts for standard atmospheric pressure at sea level, converting absolute pressure to gauge pressure.

Q2: Does atmospheric pressure change with altitude?
A: Yes, atmospheric pressure decreases with altitude. This calculator uses standard sea-level pressure (14.7 psi).

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

Q4: What's the difference between PSI and PSIG?
A: PSI is absolute pressure (including atmospheric pressure), while PSIG is pressure relative to atmospheric pressure.

Q5: When would I need this conversion?
A: When working with pressure systems that use absolute pressure measurements but need gauge pressure readings.