1. What is PSI to PSIG Conversion?

PSIG (pounds per square inch gauge) is the pressure measurement relative to atmospheric pressure, while PSI (pounds per square inch absolute) includes atmospheric pressure. The conversion accounts for standard atmospheric pressure at sea level (14.7 psi).

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: The formula subtracts atmospheric pressure from absolute pressure to give gauge pressure.

3. Importance of PSIG Calculation

Details: Most pressure gauges measure PSIG (relative to atmospheric pressure), while some scientific calculations require PSI (absolute pressure). Converting between them is essential for accurate measurements and system designs.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: Why subtract exactly 14.7 psi?
A: This is the standard atmospheric pressure at sea level. Actual atmospheric pressure varies slightly with weather and altitude.

Q2: Can PSIG be negative?
A: Yes, negative PSIG indicates vacuum pressure (pressure below atmospheric).

Q3: How does altitude affect this conversion?
A: At higher altitudes, atmospheric pressure is less than 14.7 psi, so the conversion factor should be adjusted.

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

Q5: When would I need to make this conversion?
A: When comparing gauge readings to absolute pressure specifications, or when working with systems that use different pressure references.