Millimeters of mercury at standard gravity.
mmHgs to PSI Converter — mmHg to psi
Convert mmHg (mmHg) to PSI (psi) using the exact conversion factor (1 mmhg = 0.0193367775 psi). See the formula, worked examples, conversion table, history, and common uses.
mmHgs to PSI converter
Converter
Pressure Converter
Convert pascals, bars, PSI, atmospheres, mercury columns, water columns, and engineering pressure units.
Context values
Some unit families need one extra value for a physically accurate result.
Pounds per square inch.
Result = input x 133.3223874 / 6894.757293.
Pressure uses the pascal as the base unit.
Reserved above the conversion cards and below the converter.
About Converting mmHgs to PSI
mmHg and PSI both show up on pressure gauges — psi is standard on US tire and tool specifications, while bar is the everyday pressure unit across most of the rest of the world. Specifically: Millimeters of mercury at standard gravity, and pounds per square inch.
Formula
psi = mmhgs × 0.0193367774595
This factor comes from each unit's defined relationship to the category's base unit: 1 mmhg equals 133.322387415 base units, and 1 psi equals 6894.75729317 base units, so dividing one by the other gives the direct mmhg-to-psi factor of 0.0193367774595.
Simple example
1 mmHg × 0.01933677746 = 0.0193367775 psi
1 mmhg = 0.0193367775 psi.
Real-world example
35 mmHg × 0.01933677746 = 0.6767872111 psi
35 mmhgs = 0.6767872111 psi.
Conversion table
| mmHg (mmHg) | PSI (psi) |
|---|---|
| 1 mmHg | 0.0193367775 psi |
| 5 mmHg | 0.0966838873 psi |
| 10 mmHg | 0.1933677746 psi |
| 25 mmHg | 0.4834194365 psi |
| 50 mmHg | 0.966838873 psi |
| 100 mmHg | 1.933677746 psi |
Reverse conversion: PSI to mmHg
0.0193367775 psi × 51.7149252 = 1.000000002 mmHg
0.0193367775 psi = 1.000000002 mmhgs.
mmhgs = psi × 51.7149252039
For a page dedicated to this direction, see PSI to mmHg.
Understanding the mmHg (mmHg)
Millimeters of mercury at standard gravity.
Understanding the PSI
PSI (psi) measures pressure. PSI (pounds-force per square inch) equals exactly 6,894.757293168 pascals. It is classified as a US/imperial customary unit.
Where it's used: United States (standard pressure unit for tires, tools, and plumbing)
Uses of the PSI today
- Tire pressure specifications in the US
- Hydraulic and pneumatic system ratings
- Plumbing, compressed-air tools, and industrial equipment ratings
History of the PSI
PSI is a derived unit from the pound-force and the inch, both themselves standardized through English and later international agreements rather than invented as a pressure unit from scratch.
It became the default pressure unit in US engineering as pound-force and inch-based measurement dominated American industry through the 19th and 20th centuries, and it remains in everyday use for tires and tools even as most other measurements in the US context stay imperial.
Historical origin. PSI was not the invention of a single named person; it developed through the process described above.
PSI — sources
- NIST Special Publication 811 — Guide for the Use of the International System of Units — Documents conversion factors for psi and other US customary pressure units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many psi are in 1 mmhg?
1 mmhg equals 0.0193367775 psi, using the exact defined conversion factor rather than an estimate.
How do I convert mmhg to psi?
Multiply the mmhg value by 0.01933677746. The converter above does this instantly to whatever precision you set.
How do I convert psi back to mmhg?
Use the reverse factor: 1 psi equals 51.7149252 mmhgs. You can also use the swap control in the converter above to flip the direction instantly.
What is a mmhg?
mmHg (mmHg) is a unit of pressure.
What is a psi?
PSI (psi) measures pressure. PSI (pounds-force per square inch) equals exactly 6,894.757293168 pascals. It is classified as a US/imperial customary unit.
Is the mmhg to psi conversion exact?
Yes. PSI (pounds-force per square inch) equals exactly 6,894.757293168 pascals. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.