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 mechanics work with pressure measurements in various systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( PSIG \) — Gauge pressure (psig)
• \( PSI \) — Absolute pressure (psia)
• \( 14.7 \) — Standard atmospheric pressure at sea level (psi)

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

3. Importance of PSI to PSIG Conversion

Details: Most pressure gauges read PSIG (zero at atmospheric pressure), while many calculations require absolute pressure (PSI).

4. Using the Calculator

Tips: Enter the absolute pressure in PSI. The calculator will subtract standard 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: What's the difference between PSI and PSIG?
A: PSI (absolute) includes atmospheric pressure, while PSIG (gauge) measures pressure relative to atmospheric.

Q3: When would I need this conversion?
A: When working with pressure vessels, HVAC systems, pneumatic tools, or any application where gauge pressure is used.

Q4: Does altitude affect this calculation?
A: Yes, atmospheric pressure changes with altitude. For precise work at high elevations, adjust the 14.7 value accordingly.

Q5: Can PSIG be negative?
A: Yes, negative PSIG indicates vacuum or pressure below atmospheric.