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To convert from millibar (mbar) 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 millibar (mbar) to pound per square inch (psi).
Using the formula:
Therefore, 5 millibar (mbar) is equal to pound per square inch (psi).
Here are some quick reference conversions from millibar (mbar) to pound per square inch (psi):
| millibar | pounds per square inch |
|---|---|
| 0.000001 mbar | psi |
| 0.001 mbar | psi |
| 0.1 mbar | psi |
| 1 mbar | psi |
| 2 mbar | psi |
| 3 mbar | psi |
| 4 mbar | psi |
| 5 mbar | psi |
| 6 mbar | psi |
| 7 mbar | psi |
| 8 mbar | psi |
| 9 mbar | psi |
| 10 mbar | psi |
| 20 mbar | psi |
| 30 mbar | psi |
| 40 mbar | psi |
| 50 mbar | psi |
| 100 mbar | psi |
| 1000 mbar | psi |
| 10000 mbar | psi |
For all Pressure converters, choose units using the From/To dropdowns above.
A millibar (mbar) is a metric unit used to measure atmospheric pressure.
It's most commonly used in weather forecasting and reporting.
(Technically, one millibar is equal to 0.1 kilopascal, or kPa).
Meteorologists use millibars as the primary unit to measure and report atmospheric pressure.
On weather maps, you'll see lines called isobars, which connect areas of equal pressure, drawn in millibar intervals.
Standard atmospheric pressure at sea level is about 1013 mbar.
This number is a key benchmark for weather conditions:
Yes, for all practical purposes, a millibar (mbar) and a hectopascal (hPa) are the same.
The two units are used interchangeably.
The conversion is simple: 1 mbar = 1 hPa.
While you'll still see millibars in public weather reports (especially in the U.S.), the hectopascal is the preferred SI (International System of Units) unit for global scientific consistency.
A barometer measures barometric pressure—the weight of the air above you—using millibars.
Watching the change in this reading is key to predicting the weather:
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.