Convert Pounds per Square Inch to Millimeters of Mercury
Instantly convert Pounds per Square Inch (psi) to Millimeters of Mercury (mmHg) with our free online calculator.
Formula: psi to mmHg — multiply by 51.7151
Reference Table
| Pounds per Square Inch (psi) | Millimeters of Mercury (mmHg) |
|---|---|
| 1 | 51.7151 |
| 5 | 258.575 |
| 10 | 517.151 |
| 25 | 1292.88 |
| 50 | 2585.75 |
| 100 | 5171.51 |
How to Convert Pounds per Square Inch to Millimeters of Mercury
Formula
To convert Pounds per Square Inch (psi) to Millimeters of Mercury (mmHg): multiply by 51.7151
Step-by-Step
- Start with your value in Pounds per Square Inch (psi).
- Multiply by 51.7151 to perform the conversion.
- The result is your value expressed in Millimeters of Mercury (mmHg).
Conversion Factor
1 psi = 51.7151 mmHg
Reverse Factor
1 mmHg = 0.0193367 psi
Worked Example
Convert 25 Pounds per Square Inch to Millimeters of Mercury: 25 psi = 1292.88 mmHg
About Pound per Square Inch (psi)
An imperial unit of pressure equal to one pound-force applied over one square inch (exactly 6,894.757 Pa per NIST SP 811). PSI is the dominant US pressure unit and remains the working unit in most US-built industrial, automotive, and consumer equipment: passenger-car tire inflation (32-35 psi cold), compressed air shop systems (typically 100-150 psi), hydraulic equipment (1,500-3,000 psi mobile, up to 10,000 psi on press brakes), ammunition chamber pressures (SAAMI specs in psi), municipal potable water supply (~40-80 psi at the meter), and natural gas distribution pressures. US engineering textbooks and the ASME B31 pipe codes, API piping specifications, and AWWA waterworks standards quote allowable pressures in psi. Engineers should distinguish gauge psi (psig — pressure above atmospheric) from absolute psi (psia — pressure above perfect vacuum); 0 psig = 14.696 psia at sea level. 1 psi = 6.895 kPa = 0.0689 bar = 51.715 mmHg.
About Millimeters of Mercury (mmHg)
A unit of pressure historically defined as the pressure exerted by a column of mercury exactly 1 millimeter tall at the standard acceleration of gravity (9.80665 m/s²) and the standard density of mercury (13,595.1 kg/m³ at 0 °C). The mmHg's contemporary definition rounds to exactly 133.322387415 Pa (NIST SP 811). Despite being non-SI, mmHg remains the international clinical standard for blood pressure measurement ("120 over 80" mmHg) per WHO and ESH guidelines, and is the default unit for intraocular pressure in ophthalmology (normal IOP 10-21 mmHg per Glaucoma Research Foundation) and intracranial pressure monitoring in neurology. Numerically the mmHg is almost identical to the torr (1 mmHg ≈ 1.0000007 torr — the difference is whether one uses the conventional density or the experimentally measured density of mercury). Barometric atmospheric pressure was historically quoted in mmHg before kPa/hPa adoption (760 mmHg = 1 atm = 101.325 kPa).
Quick Facts
- 1 Pound per Square Inch equals 51.7151 Millimeters of Mercury
- 1 Millimeters of Mercury equals 0.0193367 Pounds per Square Inch
- Pound per Square Inch is a unit of pressure
- Millimeters of Mercury is a unit of pressure
- This conversion is commonly used in tire inflation, weather reporting, scuba diving, and engineering
- The Pound per Square Inch belongs to the imperial system
- The Millimeters of Mercury belongs to the metric system
Common Pound per Square Inch to Millimeters of Mercury Conversions
| Pounds per Square Inch (psi) | Millimeters of Mercury (mmHg) |
|---|---|
| 0.1 | 5.17151 |
| 0.5 | 25.8575 |
| 1 | 51.7151 |
| 2 | 103.43 |
| 5 | 258.575 |
| 10 | 517.151 |
| 14.696 | 760.005 |
| 15 | 775.726 |
| 20 | 1034.3 |
| 25 | 1292.88 |
| 50 | 2585.75 |
| 100 | 5171.51 |
| 150 | 7757.26 |
| 200 | 10343 |
| 500 | 25857.5 |
| 1000 | 51715.1 |
Understanding Pounds per Square Inch
The Pound per Square Inch (symbol: psi) is a unit of pressure. An imperial unit of pressure equal to one pound-force applied over one square inch (exactly 6,894.757 Pa per NIST SP 811). PSI is the dominant US pressure unit and remains the working unit in most US-built industrial, automotive, and consumer equipment: passenger-car tire inflation (32-35 psi cold), compressed air shop systems (typically 100-150 psi), hydraulic equipment (1,500-3,000 psi mobile, up to 10,000 psi on press brakes), ammunition chamber pressures (SAAMI specs in psi), municipal potable water supply (~40-80 psi at the meter), and natural gas distribution pressures. US engineering textbooks and the ASME B31 pipe codes, API piping specifications, and AWWA waterworks standards quote allowable pressures in psi. Engineers should distinguish gauge psi (psig — pressure above atmospheric) from absolute psi (psia — pressure above perfect vacuum); 0 psig = 14.696 psia at sea level. 1 psi = 6.895 kPa = 0.0689 bar = 51.715 mmHg.
It belongs to the imperial measurement system.
Pounds per Square Inch are commonly used in tire inflation, weather reporting, scuba diving, and engineering.
Understanding Millimeters of Mercury
The Millimeters of Mercury (symbol: mmHg) is a unit of pressure. A unit of pressure historically defined as the pressure exerted by a column of mercury exactly 1 millimeter tall at the standard acceleration of gravity (9.80665 m/s²) and the standard density of mercury (13,595.1 kg/m³ at 0 °C). The mmHg's contemporary definition rounds to exactly 133.322387415 Pa (NIST SP 811). Despite being non-SI, mmHg remains the international clinical standard for blood pressure measurement ("120 over 80" mmHg) per WHO and ESH guidelines, and is the default unit for intraocular pressure in ophthalmology (normal IOP 10-21 mmHg per Glaucoma Research Foundation) and intracranial pressure monitoring in neurology. Numerically the mmHg is almost identical to the torr (1 mmHg ≈ 1.0000007 torr — the difference is whether one uses the conventional density or the experimentally measured density of mercury). Barometric atmospheric pressure was historically quoted in mmHg before kPa/hPa adoption (760 mmHg = 1 atm = 101.325 kPa).
It belongs to the metric measurement system.
Millimeters of Mercury are commonly used in tire inflation, weather reporting, scuba diving, and engineering.
Why Convert Pounds per Square Inch to Millimeters of Mercury?
Engineers, mechanics, and scientists frequently need to convert pressure between Pounds per Square Inch and Millimeters of Mercury when working with different measurement standards. Tire pressure, blood pressure readings, weather barometric measurements, and industrial process specifications may all use different pressure units depending on the region or discipline. Reliable conversion prevents equipment misuse and ensures safety.
Frequently Asked Questions
How do I convert Pounds per Square Inch to Millimeters of Mercury?
An imperial unit of pressure equal to one pound-force applied over one square inch (exactly 6,894. To convert Pounds per Square Inch to Millimeters of Mercury, multiply by 51.7151. For example, 25 psi equals 1292.88 mmHg.
How many Millimeters of Mercury are in 1 Pound per Square Inch?
There are 51.7151 Millimeters of Mercury in 1 Pound per Square Inch.
How many Pounds per Square Inch are in 1 Millimeters of Mercury?
There are 0.0193367 Pounds per Square Inch in 1 Millimeters of Mercury.
What is the formula for Pound per Square Inch to Millimeters of Mercury conversion?
The formula is: multiply by 51.7151. This means 1 psi = 51.7151 mmHg.
Is a Pound per Square Inch bigger than a Millimeters of Mercury?
No. One Pound per Square Inch is smaller than one Millimeters of Mercury because 1 psi equals 51.7151 mmHg, which is greater than 1.
When do you need to convert between Pounds per Square Inch and Millimeters of Mercury?
A unit of pressure historically defined as the pressure exerted by a column of mercury exactly 1 millimeter tall at the standard acceleration of gravity (9. Pound per Square Inch and Millimeters of Mercury are both pressure units, so conversion comes up whenever one source of information uses one unit and another uses the other — a classic cross-reference challenge in engineering, trade, travel, and everyday life.