What this converts
Bar to pounds per square inch, using the exact factor 1 bar = 14.5038 psi. Type a bar value, the psi reads out instantly. So 2 bar is 29.0 psi, and 2.5 bar lands at 36.3 psi. No submit button, no waiting on a server.
Bar is the metric-ish unit you’ll see on European gauges, dive computers, and espresso machines. Psi is what American tire shops, compressors, and pressure washers use. Crossing between them is constant once you start working with imported equipment.
Three places this matters
Pressure conversion sounds dry until you’re standing at a gas station air pump with a tire spec in bar.
- Tire pressure. European cars list recommended pressure in bar on the door jamb; US air pumps read psi. A common 2.2 bar spec is 31.9 psi, and 2.5 bar is 36.3 psi. Get this wrong and you’re driving on under- or over-inflated tires.
- Espresso machines. The classic extraction pressure is 9 bar, which is 130.5 psi. Machine specs and pressure gauges sometimes mix the two units, so converting helps when you’re dialing in a shot or reading a pump rating.
- Scuba diving. Tank and depth pressures are usually metric (bar) in most of the world, but US gear and some gauges show psi. A full tank around 200 bar is roughly 2901 psi. The conversion is also why “300 bar” and “4500 psi” tanks describe similar high-pressure fills.
The reference table
The tool includes a quick-lookup table for the values that come up most:
| bar | psi | Typical use |
|---|---|---|
| 2.0 | 29.0 | Small car tires |
| 2.2 | 31.9 | Common car tire spec |
| 2.5 | 36.3 | Loaded car, SUV tires |
| 3.0 | 43.5 | Light truck tires |
| 9.0 | 130.5 | Espresso extraction |
| 200 | 2901 | Full scuba tank |
For tire work you mostly live in the 2 to 3 bar range, so those rows cover the bulk of real use. The free input handles anything outside the table.
How the math works
Pressure is force over area, and the two units just measure that force-per-area against different reference units. One bar is defined as 100,000 pascals, and one psi is the pressure of one pound-force on a square inch. Run the unit algebra and a bar comes out to 14.5038 psi exactly. There’s no offset like temperature has, so it’s a straight multiply: bar times 14.5 gets you a close psi, and the full 14.5038 factor keeps it precise. That exact factor is what the tool uses under the hood.
Type any bar value and the psi result updates as you go. Everything calculates in your browser, so nothing you enter is uploaded, and it keeps working offline after the page loads.
FAQ
What is 1 bar in psi?
14.5038 psi. The tool uses this exact factor, so even odd values like 2.3 bar convert precisely (33.4 psi).
What’s the right tire pressure conversion?
A typical European spec of 2.2 to 2.5 bar is 31.9 to 36.3 psi. Always check your specific car’s door jamb or manual for the recommended figure, then convert it for a psi air pump.
How many psi is 9 bar for espresso?
130.5 psi. Nine bar is the traditional espresso extraction pressure, which is why it shows up on machine gauges and pump specs.
Is bar bigger than psi?
Much bigger per unit. One bar equals about 14.5 psi, so any pressure has a far larger number in psi than in bar. That’s why tire specs look like “2.4” in bar but “35” in psi.
Does this run locally?
Yes. It’s browser-side arithmetic with a fixed factor, so your values never leave the device and it works without an internet connection once loaded.