Pressure Converter
Tire Pressure: PSI vs. Bar
The most common daily use for pressure conversion is inflating car or bike tires. However, the units depend on where your car (or pump) was manufactured.
- PSI (Pounds per Square Inch): The standard in the USA. A typical car tire is inflated to 32-35 PSI.
- Bar: The metric standard used in Europe. A typical car tire is 2.2 - 2.4 Bar.
If you try to inflate a European tire to "32 Bar" instead of "32 PSI," the tire will explode violently. Always check the unit on your gauge!
What is "1 Atmosphere"?
We don't feel it, but the air around us has weight. At sea level, the weight of the air pressing down on your body is exactly 1 Atmosphere (atm).
This unit is crucial for Scuba Divers. For every 10 meters (33 feet) you dive underwater, the pressure increases by 1 atm.
- Surface: 1 atm
- 10m Deep: 2 atm (1 from air, 1 from water)
- 20m Deep: 3 atm
Pascal: The Scientific Standard
While we use PSI and Bar for daily life, scientists use the Pascal (Pa). It is the official SI unit of pressure.
However, a Pascal is tiny. It represents the force of one newton per square meter. That is roughly the weight of a single dollar bill resting on a table. Because it is so small, you will usually see it written as kPa (Kilopascals) or MPa (Megapascals) for engineering.
Conversion Cheat Sheet
| Unit | PSI Equivalent | Pascal Equivalent |
|---|---|---|
| 1 PSI | 1 | 6,895 Pa |
| 1 Bar | 14.5 PSI | 100,000 Pa |
| 1 Atm | 14.7 PSI | 101,325 Pa |
| 1 Torr | 0.019 PSI | 133 Pa |