PSI to inHg Converter
Convert pounds per square inch to inches of mercury — used for vacuum measurement. Results update as you type; exact factors shown.
One pound per square inch is 2.036 inches of mercury — see the exact factor, not a rounded rule of thumb.
How the psi to inhg converter works
Pressures convert through the pascal (1 N/m²). One bar is exactly 100 kPa; a standard atmosphere is exactly 101.325 kPa; 1 psi is 6.894757 kPa (a pound-force on a square inch); 1 mmHg is 133.322 Pa by the conventional definition.
Australia is fully metric under the National Measurement Act 1960; imperial units appear only in trade with the US and in older documents.
Common pressure conversions
| From | To | Units |
|---|---|---|
| 0.5 psi | 1.018 inHg | pounds per square inch to inches of mercury |
| 1 psi | 2.036 inHg | pound per square inch to inches of mercury |
| 2 psi | 4.072 inHg | pounds per square inch to inches of mercury |
| 5 psi | 10.1801 inHg | pounds per square inch to inches of mercury |
| 10 psi | 20.3602 inHg | pounds per square inch to inches of mercury |
| 14.696 psi | 29.9214 inHg | pounds per square inch to inches of mercury |
| 15 psi | 30.5403 inHg | pounds per square inch to inches of mercury |
| 20 psi | 40.7204 inHg | pounds per square inch to inches of mercury |
| 25 psi | 50.9005 inHg | pounds per square inch to inches of mercury |
| 30 psi | 61.0806 inHg | pounds per square inch to inches of mercury |
| 50 psi | 101.801 inHg | pounds per square inch to inches of mercury |
| 100 psi | 203.602 inHg | pounds per square inch to inches of mercury |
Units in this converter and their exact factors
| Unit | Symbol | One unit in pascals |
|---|---|---|
| pascal | Pa | 1 pascal |
| kilopascal | kPa | 1,000 pascal |
| megapascal | MPa | 1,000,000 pascal |
| bar | bar | 100,000 pascal |
| millibar (hectopascal) | mbar | 100 pascal |
| standard atmosphere | atm | 101,325 pascal |
| pound per square inch | psi | 6,894.757293168 pascal |
| millimetre of mercury | mmHg | 133.322387415 pascal |
| inch of mercury | inHg | 3,386.389 pascal |
FAQFrequently asked questions about pressure conversion
How many inHg is 1 psi?
2.036 inHg.
What is 14.696 psi?
One atmosphere, which is 29.92 inHg.
Where is inHg used for vacuum?
Engine manifold vacuum and HVAC service gauges, where a reading of 25 inHg means 25 below atmospheric.
What is full vacuum in inHg?
29.92 inHg below atmospheric, at sea level.
What is 5 psi in inHg?
10.18 inHg.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Measurement Institute (NMI) — Australia's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.