Pressure converters
Convert between bar, PSI and kPa. Includes a pressure-to-water-depth calculator for diving, plumbing and hydraulics. Instant results for tyres, engineering and industrial work.
Last updated: May 2026
Bar and PSI
Bar and PSI are the two most common pressure units. Bar is standard in most of Europe; PSI dominates in the US and UK for tyres, air tools and hydraulic systems.
Bar and kPa
Kilopascals appear in weather reports, HVAC specs and some industrial datasheets. One bar equals exactly 100 kPa.
Pressure and depth
Water pressure increases with depth at a predictable rate. Useful for diving, submarine cables, plumbing and tank design.
When you need a pressure converter
Pressure unit confusion is most common with tyres (bar vs PSI), air compressors (both units appear on tools and gauges), and weather data (hPa or kPa vs millibar). The unit on your gauge and the unit in the spec are often different, so converting once before you act is the safest approach.
Quick reference: 1 bar = 14.504 PSI = 100 kPa.
Pressure unit conversion factors
| Conversion | Multiply by | Example |
|---|---|---|
| bar to PSI | 14.504 | 2.5 bar = 36.3 PSI |
| PSI to bar | 0.0689 | 32 PSI = 2.21 bar |
| bar to kPa | 100 | 2 bar = 200 kPa |
| kPa to bar | 0.01 | 250 kPa = 2.5 bar |
| PSI to kPa | 6.895 | 32 PSI = 220.6 kPa |
Typical pressures for everyday applications
Understanding where a given pressure value sits in context helps when reading specs, setting gauges or troubleshooting equipment. The table below shows real-world pressure values for the most common applications, in both bar and PSI.
| Application | Typical pressure (bar) | Typical pressure (PSI) | Notes |
|---|---|---|---|
| Car tyre (standard) | 2.2 to 2.5 | 32 to 36 | Check door sticker, not sidewall max |
| Car tyre (SUV / loaded) | 2.5 to 3.0 | 36 to 44 | Front and rear may differ |
| Road bicycle tyre | 6 to 8 | 87 to 116 | Narrow tyres need higher pressure |
| Mountain bike tyre | 1.5 to 2.5 | 22 to 36 | Lower for grip on loose surfaces |
| Espresso machine (brew) | 9 | 130 | Optimal extraction pressure; set internally |
| Scuba diving cylinder | 200 to 300 | 2900 to 4350 | Full fill for a standard aluminium 80 tank |
| Atmospheric (sea level) | 1.013 | 14.7 | Baseline for absolute pressure calculations |
Which pressure unit to expect and why
The unit you see depends almost entirely on the industry and country. Tyre pressure in the US is always in PSI; in Europe you fill to a bar value; in Australia and parts of Asia the label prints kPa. A tyre marked at 2.4 bar needs 34.8 PSI or 240 kPa: the same inflation, three different numbers. Petrol-station pumps in different countries label their units differently, so knowing the conversion before you travel prevents significant under- or over-inflation.
Industrial and engineering pressure units fragment further. HVAC datasheets commonly use Pa or kPa. Hydraulic systems in Europe use bar; in the US they use PSI, often reaching thousands of PSI for high-pressure circuits. Boiler and steam specs sometimes print in MPa. Weather pressure is given in hPa (hectopascals) on most European meteorological reports, and in inHg (inches of mercury) in the US aviation METAR format. One hPa equals 1 mbar, so a standard sea-level atmospheric pressure of 1013.25 hPa and 1013.25 mbar are the same number by design.
The gauge/absolute distinction matters in technical work. Gauge pressure (PSIG, barg) is measured relative to atmospheric; absolute pressure (PSIA, bara) is measured relative to a perfect vacuum. A car tyre at 2.4 bar gauge is at about 3.4 bar absolute, because atmospheric pressure adds roughly 1 bar on top. Most workshop tools and consumer gauges read gauge pressure. Vacuum gauges and scientific instruments typically use absolute. Mixing the two in a calculation produces errors equal to one atmosphere, roughly 1 bar or 14.5 PSI.
Frequently Asked Questions
What is 32 PSI in bar?
About 2.21 bar, or roughly 221 kPa. Multiply PSI by 0.069 to get bar. Many car tyres sit between 2.2 and 2.5 bar (32 to 36 PSI), but always use the figure on the door sticker.
Is kPa the same as hPa or millibar in a weather report?
They are directly related: 1 kPa equals 10 hPa equals 10 millibar. Typical sea-level pressure is about 1013 hPa, which is 101.3 kPa or 1.013 bar.
How much does water pressure rise with depth?
By about 1 bar (roughly 14.5 PSI) for every 10 metres of water, on top of the 1 bar of atmosphere at the surface. The pressure to water depth tool converts between the two.
What is the difference between gauge and absolute pressure?
Gauge pressure is measured relative to the surrounding air, which is what a tyre or compressor gauge shows. Absolute pressure adds the roughly 1 bar of atmospheric pressure. Tyre and tool specs are normally gauge pressure.
Why do compressor gauges show both bar and PSI?
Because tools, fittings and tyres are sold in both systems. Check which unit the equipment spec uses before setting a regulator, since 6 bar and 6 PSI are very different pressures.
What pressure should my car tyres be?
Check the door jamb label or owner's manual, not the maximum pressure stamped on the tyre sidewall. Common values are 2.2 to 2.5 bar (32 to 36 PSI) for standard saloons and 2.5 to 3.0 bar (36 to 44 PSI) for SUVs or heavy loads. Front and rear pressures are often slightly different.
What is the correct pressure for an espresso machine?
Pump espresso machines brew at around 9 bar (130 PSI). This is set internally by the pump and overpressure valve, not something you adjust on consumer machines. The boiler pressure for steam is typically 1 to 1.5 bar. The gauge on the machine shows pump pressure during extraction, not boiler pressure.
What is atmospheric pressure in bar and PSI?
Standard sea-level atmospheric pressure is 1.013 bar or 14.7 PSI (also 1013.25 hPa or 101.3 kPa). This is the baseline for gauge pressure: a tyre reading of 0 PSI on a gauge means the tyre is at atmospheric pressure, not a vacuum. Absolute pressure adds atmospheric pressure to the gauge reading.