How many PSI is 1 inHg?

1 inch of mercury (inHg) equals approximately 0.491154 pounds per square inch (PSI). This is based on mercury density at 0 °C (32 °F) under standard gravity, as defined by international standards.

How do I convert inHg to PSI manually?

Multiply the inHg value by 0.491154. For example, 29.92 inHg × 0.491154 ≈ 14.696 psi (standard sea-level atmospheric pressure). To convert PSI back to inHg, divide by 0.491154.

What is standard atmospheric pressure in inHg and PSI?

Standard atmospheric pressure is 29.9213 inHg, which equals 14.6959 PSI. Weather forecasters in the US commonly report barometric pressure in inHg, while engineers often work in PSI.

What does inHg measure?

Inches of mercury (inHg) is a pressure unit that represents the height of a mercury column supported by the pressure. It is widely used in barometry (weather), aviation altimetry, and vacuum measurement in HVAC and automotive applications.

What is 30 inHg in PSI?

30 inHg equals approximately 14.73 PSI. This is close to standard atmospheric pressure and is a common reference point in weather reporting and aviation.

When would I use inHg versus PSI?

Inches of mercury (inHg) is standard in US weather forecasting, aviation, and HVAC vacuum measurement. PSI is the US standard for tire pressure, hydraulics, and most mechanical engineering specs. Use this converter whenever specs are given in one unit but your application requires the other.

inHg to PSI Converter

Name: inHg to PSI Converter
Availability: InStock
Author: Nham Vu

Enter a pressure in inches of mercury (inHg) and get the PSI equivalent instantly, with reverse conversion included.

Converter

Pressure in inches of mercury (inHg)

Result in PSI

Reverse: PSI to inHg

Pressure in PSI

Result in inHg

Reference Table

inHg PSI

1 inHg 0.4912

5 inHg 2.4558

10 inHg 4.9115

15 inHg 7.3673

20 inHg 9.8231

25 inHg 12.279

29.92 inHg 14.696

30 inHg 14.735

35 inHg 17.190

40 inHg 19.646

50 inHg 24.558

100 inHg 49.115

Summary

Enter a pressure in inches of mercury (inHg) and get the PSI equivalent instantly, with reverse conversion included.

How it works

Enter the pressure value in inches of mercury (inHg) in the top input field.
The PSI result appears instantly with no button press needed.
Use the reverse field to convert PSI back to inHg.
Click "Copy" next to any result to copy the value to your clipboard.
Check the reference table for common inHg-to-PSI values at a glance.

Use cases

Convert barometric pressure readings from weather stations that report in inHg to PSI.
Translate vacuum gauge readings (in inHg) to PSI for HVAC and automotive work.
Check manifold absolute pressure (MAP) sensor specs given in inHg against PSI datasheets.
Convert altimeter settings reported in inHg to PSI for engineering calculations.
Compare tire inflation reference charts that mix inHg and PSI pressure units.
Verify refrigeration system low-side pressure readings between inHg and PSI scales.
Convert barometric pressure data for meteorological or scientific reports.
Cross-reference medical ventilator pressure specs listed in inHg against PSI limits.

Frequently Asked Questions

Last updated: 2026-07-23 · Reviewed by Nham Vu