1. What is Gauge Pressure?

Definition: Gauge pressure is the pressure relative to atmospheric pressure. It's the difference between absolute pressure and atmospheric pressure.

Purpose: This calculator helps determine the gauge pressure when you know the absolute pressure and atmospheric pressure.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_g \) — Gauge pressure (Pascals)
• \( P \) — Absolute pressure (Pascals)
• \( P_{atm} \) — Atmospheric pressure (Pascals, default 101325 Pa)

Explanation: Gauge pressure is calculated by subtracting atmospheric pressure from absolute pressure.

3. Importance of Gauge Pressure

Details: Gauge pressure is commonly used in various applications like tire pressure measurements, HVAC systems, and industrial processes.

4. Using the Calculator

Tips: Enter the absolute pressure and atmospheric pressure (default is standard atmospheric pressure at sea level: 101325 Pa). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between gauge and absolute pressure?
A: Absolute pressure is measured relative to a perfect vacuum, while gauge pressure is measured relative to atmospheric pressure.

Q2: Why is atmospheric pressure set to 101325 Pa by default?
A: This is the standard atmospheric pressure at sea level. Adjust if working at different altitudes.

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

Q4: What are common units for pressure?
A: Pascals (Pa), bars, psi, mmHg, atm. This calculator uses Pascals.

Q5: How does altitude affect gauge pressure?
A: Higher altitudes have lower atmospheric pressure, which affects gauge pressure readings.