🔁 Conversion
Converting psi to Bar (and Other Pressure Units)
The exact factor for turning psi into bar, a quick tyre-pressure reference, and how pascals, kPa, bar, psi, atmospheres and mmHg relate to each other.
Updated 19 October 2026 · 2 min read
Pump up a tyre, read a weather chart or check a boiler gauge and you'll meet several different pressure units. The two you'll trip over most are psi (pounds per square inch), common in the UK and US, and bar, used across much of Europe. Converting between them is a single multiplication.
The exact conversion
A rough mental shortcut: 1 bar ≈ 14.5 psi, so to go from bar to psi you multiply by roughly 14.5, and to go the other way you divide by it. For quick checks that's close enough; for anything precise, use the full factor.
A quick tyre-pressure reference
Car tyre pressures are often quoted in bar on the door sticker but shown in psi on a forecourt pump. These pairings cover most everyday cases:
- 28 psi ≈ 1.93 bar
- 30 psi ≈ 2.07 bar
- 32 psi ≈ 2.21 bar
- 35 psi ≈ 2.41 bar
- 40 psi ≈ 2.76 bar
Always follow the pressure your vehicle's manufacturer specifies rather than a general figure — it's printed inside the driver's door frame or in the handbook, and may differ front to back or when fully loaded.
The other pressure units
All pressure units measure force spread over an area, so they all convert through a common base — the pascal (Pa), the SI unit of one newton per square metre. The pascal is tiny, so everyday values use larger units:
- Kilopascal (kPa): 1,000 pascals. Many car manuals use kPa; 1 bar = 100 kPa.
- Bar: 100,000 pascals, close to average sea-level air pressure.
- Atmosphere (atm): defined as standard sea-level pressure, 101,325 Pa.
- mmHg (millimetres of mercury): used for blood pressure and barometers; about 133.3 Pa each.
Because every unit maps onto pascals, converting any pair is just two steps: into pascals, then out to the unit you want. The pressure converter does this in one go and shows the result in every unit at once — handy when the gauge, the manual and the pump all disagree. For the wider picture of unit systems, see metric versus imperial, and for another everyday conversion there's turning mph into km/h.
Frequently asked questions
- How do I convert psi to bar?
- Multiply the psi figure by 0.0689476. For example, 32 psi × 0.0689476 ≈ 2.21 bar. To go back, divide by the same number, or multiply bar by 14.5038.
- Is 1 bar the same as 1 atmosphere?
- They're very close but not identical. One bar is exactly 100,000 pascals, while one standard atmosphere is 101,325 pascals — about 1.3% higher. For most practical purposes they're treated as roughly the same.
- What pressure should my car tyres be?
- Use the figure your manufacturer specifies, found on a sticker inside the driver's door frame or in the handbook. It's often given in both psi and bar and can differ between front and rear or when the car is heavily loaded.