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To convert from millimeter of mercury (mmHg) to pound per square inch (psi), use the following formula:
With is the ratio between the base units kilopound per square inch (ksi) and kilopascal (kPa).
Let's convert 5 millimeter of mercury (mmHg) to pound per square inch (psi).
Using the formula:
Therefore, 5 millimeter of mercury (mmHg) is equal to pound per square inch (psi).
Here are some quick reference conversions from millimeter of mercury (mmHg) to pound per square inch (psi):
| millimeters of mercury | pounds per square inch |
|---|---|
| 0.000001 mmHg | psi |
| 0.001 mmHg | psi |
| 0.1 mmHg | psi |
| 1 mmHg | psi |
| 2 mmHg | psi |
| 3 mmHg | psi |
| 4 mmHg | psi |
| 5 mmHg | psi |
| 6 mmHg | psi |
| 7 mmHg | psi |
| 8 mmHg | psi |
| 9 mmHg | psi |
| 10 mmHg | psi |
| 20 mmHg | psi |
| 30 mmHg | psi |
| 40 mmHg | psi |
| 50 mmHg | psi |
| 100 mmHg | psi |
| 1000 mmHg | psi |
| 10000 mmHg | psi |
For all Pressure converters, choose units using the From/To dropdowns above.
A millimeter of mercury (mmHg) is a manometric unit of pressure.
It was historically defined as the pressure generated by a column of mercury exactly one millimeter high.
Today, it is most famous as the unit used in medicine for measuring blood pressure. It is also commonly used in meteorology, aviation, and physics to measure atmospheric pressure or vacuum pressure.
The mmHg unit originates from the invention of the barometer by Evangelista Torricelli in 1643.
Torricelli's device measured atmospheric pressure by seeing how high it could support a column of mercury in a tube.
Standard atmospheric pressure was found to support a column approximately 760 mm high, which established 760 mmHg as a standard reference point.
The most well-known application of mmHg is in medicine.
Blood Pressure: Readings are given as two numbers: systolic pressure (when the heart beats) over diastolic pressure (when the heart rests), such as 120/80 mmHg. This is a critical vital sign for human health.
Meteorology: Used for reporting barometric (atmospheric) pressure, which helps in weather forecasting.
Physics & Engineering: Used for measuring vacuum pressures and other low-pressure systems where precision is needed.
While mmHg is common, other pressure units are standard in different fields. Here are the most common conversions:
A pound per square inch (PSI) is a unit of pressure commonly used in the imperial system (which is standard in the United States).
It measures the amount of force applied over a single square inch of area.
PSI is a critical measurement for safety and performance in many common items, including:
Vehicle Tires: Proper tire pressure (PSI) ensures optimal handling, fuel efficiency, and tire life. You can find the recommended level on a sticker inside the driver's door.
Home Water Pressure: Affects everything from shower performance to how well appliances like dishwashers and washing machines function.
Sports Equipment: Items like footballs, basketballs, and soccer balls require a specific PSI to perform correctly and safely.
Tools: Air compressors, pressure washers, and paint sprayers all have specific PSI ratings for safe and effective operation.
While PSI is standard in the imperial system, scientific and international contexts use metric (SI) units like the Pascal (Pa) and the bar.
PSI to Pascal (Pa): The official SI unit for pressure.
1 PSI ≈ 6,894.76 Pascals (or 6.895 kilopascals, kPa).
PSI to Bar: A common unit in automotive and weather contexts. 1 bar is roughly equal to atmospheric pressure at sea level.
1 PSI ≈ 0.0689 bar.
The term "PSI" can be specified further to give more context:
PSIG (Pound-force per square inch gauge): Measures pressure relative to the surrounding atmospheric pressure. This is the most common measurement, used by a standard tire gauge.
PSIA (Pound-force per square inch absolute): Measures pressure relative to a perfect vacuum (absolute zero pressure).
The formula is: PSIA = PSIG + local atmospheric pressure.
PSID (Pound-force per square inch differential): Measures the difference in pressure between two separate points in a system, such as across a filter or valve.