How to use the psi to bar converter
- Enter a pressure value in the psi field or the bar field.
- The converter calculates the equivalent pressure in the other unit immediately.
- Results are rounded to four decimal places for practical use while retaining full precision internally.
How the psi to bar conversion works
The conversion relies on a single fixed factor derived from the definitions of both units. One pound per square inch (psi) equals exactly 0.06894757293168361 bar. The formula to convert psi to bar is:
bar = psi × 0.06894757293168361
To go the other direction, divide by that factor or multiply by its reciprocal:
psi = bar / 0.06894757293168361
For example, a typical car tire inflated to 32 psi converts as follows: 32 × 0.06894757293168361 = 2.2063 bar. Conversely, a scuba cylinder filled to 200 bar equals 200 / 0.06894757293168361 = 2,900.7548 psi.
Common pressure conversions reference table
This table lists frequently encountered pressures converted between psi and bar. Values are rounded to four decimal places.
| PSI | Bar | Typical use |
|---|---|---|
| 14.5038 | 1 | Reference: 1 bar |
| 14.6959 | 1.0133 | Standard atmosphere |
| 29.0075 | 2 | Approximate 2 bar |
| 32 | 2.2063 | Car tire pressure |
| 43.5113 | 3 | Road bicycle tire |
| 100 | 6.8948 | Industrial air line |
| 145.0377 | 10 | Hydraulic system |
Understanding psi and bar
PSI stands for pounds per square inch. It measures force in pounds applied to an area of one square inch. This unit is standard in the United States and the United Kingdom for applications like tire inflation, compressed air systems, and hydraulic machinery.
The bar is a metric unit of pressure defined as exactly 100,000 pascals. It was introduced by the Norwegian meteorologist Vilhelm Bjerknes in 1906. Although not part of the International System of Units (SI), the bar is widely used in Europe and in scientific fields because it is very close to the average atmospheric pressure at sea level (1.01325 bar). Meteorologists often use the millibar (mbar), which is one thousandth of a bar, for weather maps.
Practical applications for pressure conversion
Converting between psi and bar comes up regularly when working with equipment manufactured in different regions. A mechanic servicing an imported European vehicle may find the recommended tire pressure listed in bar on the door placard but needs to set a gauge calibrated in psi. Similarly, divers traveling internationally must understand their tank fill pressures regardless of which unit the local dive shop uses.
In industrial settings, pneumatic tools and compressors often have specifications in both units. Using this psi to bar converter ensures you apply the correct pressure without manual arithmetic errors. For contexts where you need to work with SI base units directly, converting to pascals to psi provides another useful reference point.
Common mistakes to avoid
A frequent error is confusing absolute pressure with gauge pressure. Most tire gauges read gauge pressure, meaning they measure the pressure above the ambient atmosphere. If a tire reads 32 psi on a gauge, the absolute pressure inside is actually about 46.7 psi (32 plus roughly 14.7 for atmospheric pressure). When converting for thermodynamic formulas, always confirm whether the source value is absolute or gauge.
Another mistake is rounding too early in multi-step calculations. Keep the full precision of the conversion factor (0.06894757293168361) until the final step, then round the displayed result. Early rounding compounds errors, especially in high-pressure hydraulic systems where small deviations can affect safety margins.
Worked examples
Each result below was produced by the same code the tool runs, so you can check your own numbers against them.
| Example | Input | Result |
|---|---|---|
| Car tire at 32 psi | Pressure (psi): 32 | Bar: 2.2063; Input (psi): 32 |
| Scuba tank at 200 bar | Pressure (bar): 200 | PSI: 2,900.7548; Input (bar): 200 |
| Standard atmosphere | Pressure (psi): 14.6959 | Bar: 1.0132; Input (psi): 14.6959 |
| Bicycle tire at 6 bar | Pressure (bar): 6 | PSI: 87.0226; Input (bar): 6 |
FAQ
How many bar are in 1 psi?
One psi equals approximately 0.06895 bar. The exact conversion factor is 0.06894757293168361 bar per psi.
How do I convert bar to psi?
Divide the bar value by 0.06894757293168361. For example, 2 bar divided by that factor gives 29.0075 psi.
Is bar the same as atmosphere (atm)?
No. One standard atmosphere equals 1.01325 bar. They are close but not identical, so they should not be used interchangeably in precise work.
Why do some countries use psi and others use bar?
PSI originates from the imperial system and remains common in the US and UK. The bar is a metric unit preferred in most of Europe and in scientific contexts because it relates closely to atmospheric pressure.
Does this tool upload my data?
No. The psi to bar converter runs entirely in your browser. All calculations happen locally on your device, and no values are sent to any server.
What is the difference between gauge and absolute pressure?
Gauge pressure measures the difference from ambient atmospheric pressure, while absolute pressure includes the atmosphere. A reading of 0 psi on a gauge means the pressure equals the surrounding air, not a vacuum.