💨 Pressure Converter
Convert between bar, psi, kPa, and atm instantly.
Whether you’re inflating your car tires, checking the weather forecast, planning a scuba dive, or working on an engineering project, accurate pressure conversions matter. Our Pressure Converter makes it simple to switch between bar, PSI, kPa, and atmospheres (atm) — four of the most commonly used pressure units worldwide.
Imagine you’re driving a European car in the US, and the owner’s manual recommends tire pressure of 2.3 bar — but the gas station air pump reads in PSI. Just enter 2.3 in the value field, select bar as “From” and PSI as “To”. The result appears instantly: 2.3 bar = 33.36 PSI. No mental math, no guesswork, and no risk of under- or over-inflating your tires.
Beyond the garage, this converter has plenty of practical uses. Divers check tank pressures and depth equivalents in bar and atm before heading underwater. Weather enthusiasts convert between kPa and atm to read international barometric pressure charts. Engineers and HVAC technicians routinely switch between units when working with equipment sourced from different countries, each using its own standard.
The converter uses fixed conversion factors: 1 bar = 14.5038 PSI, 1 bar = 100 kPa, and 1 atm = 1.01325 bar. These are physical constants, so your results will be consistent with scientific and industrial standards worldwide. Whether you’re a hobbyist or a professional, you can count on the numbers being right.
How the conversion works
Every pressure unit in this tool is expressed in bar as its base unit. The converter stores a fixed factor for each unit — the number of bars it represents:
- 1 bar = 1 bar
- 1 PSI = 0.0689476 bar
- 1 kPa = 0.01 bar (so 1 bar = 100 kPa)
- 1 atm = 1.01325 bar
To convert between any two units, the tool uses a single two-step path:
- Convert your amount into bars. Multiply your amount by the “from” unit’s factor. So 32 PSI × 0.0689476 = 2.2063 bar.
- Convert those bars into the target unit. Divide by the “to” unit’s factor. So 2.2063 bar ÷ 1.01325 = 2.18 atm.
This guarantees consistent results in every direction, because each unit always resolves back to the same physical base.
Worked example: Your dive computer shows a tank pressure of 200 bar and you want it in atm. 200 ÷ 1.01325 = 197.38 atm. Divers often work in bar, while physics texts use atm, so this conversion comes up constantly.
Worked example: A weather report in Europe says 1,013 hPa (hectopascals, equivalent to 101.3 kPa). To express that in atm: 101.3 kPa ÷ 100 = 1.013 bar, then ÷ 1.01325 = 1 atm — confirming it’s standard sea-level pressure.
Practical examples with real data
The table below is worked out by hand using the exact constants built into the tool. These are fixed physical relationships, so the results match what the converter returns exactly.
| From | Amount | To | Result |
|---|---|---|---|
| bar | 2.3 | psi | 33.36 psi |
| psi | 32 | bar | 2.21 bar |
| atm | 1 | kPa | 101.33 kPa |
| bar | 2.5 | atm | 2.47 atm |
| kPa | 100 | psi | 14.50 psi |
| bar | 200 | atm | 197.38 atm |
A couple worth calling out: 32 psi → bar is 32 × 0.0689476 = 2.2063, rounded to 2.21 bar — the typical recommended tire pressure for many cars. And 100 kPa → psi is 100 × 0.01 = 1 bar, then 1 ÷ 0.0689476 = 14.50 psi, which is why 1 bar ≈ 14.5 psi.
Edge cases and rounding
- Tire pressure is often stated in bar or psi. The converter handles both, but remember that car manuals specify whether they mean bar, PSI, or kPa. Entering 2.3 bar when you meant 2.3 psi gives a very different result.
- Results round to 4 decimal places. This is plenty for technical work but far more than you need for tire inflation, where rounding to one decimal is fine.
- Standard atmosphere vs. bar. 1 atm is slightly more than 1 bar (1 atm = 1.01325 bar). At diving depths and low pressures the difference matters, so don’t treat bar and atm as identical.
- kPa vs. hPa. A hectopascal equals a kilopascal’s tenth — actually 1 hPa = 0.1 kPa. Weather reports often use hPa, which is numerically equal to mbar. If you enter a weather reading in hPa, convert it to kPa first (divide by 10).
- Zero and small values. Entering 0 gives 0 in every unit. Small pressures near vacuum convert correctly, with 4-decimal precision preserving the detail.
Frequently Asked Questions
Frequently Asked Questions
Which pressure units does this converter support?
This tool supports four of the most widely used pressure units: bar (common in Europe and industrial settings), PSI (pounds per square inch, standard in the US), kPa (kilopascals, used in science and weather), and atm (atmospheres, used in diving and physics).
How do I convert PSI to bar for tire pressure?
Select PSI as "From" and bar as "To", then enter the pressure reading from your tire gauge or pump. For example, 32 PSI = 2.21 bar. Most European car manuals specify tire pressure in bar, making this a common use case for travelers and imported vehicle owners.
What's the difference between kPa and bar?
A kilopascal (kPa) is 1/100th of a bar. More precisely, 1 bar = 100 kPa. kPa is commonly used in meteorology for atmospheric pressure readings (standard sea-level pressure is about 101.325 kPa), while bar is more common in engineering and industrial applications.
Why does the result show 4 decimal places?
Pressure conversions often involve non-round conversion factors (e.g., 1 bar = 14.5038 PSI), so 4 decimal places provide useful precision for technical and scientific work. For everyday uses like tire inflation, rounding to 1-2 decimal places is usually sufficient.
Is 1 atmosphere the same as 1 bar?
No — 1 standard atmosphere (atm) equals 1.01325 bar, so they are close but not identical. An atmosphere is defined as the average pressure of Earth's atmosphere at sea level, while a bar is a round metric unit. The difference matters for diving and precise engineering calculations.
What is the pressure at typical scuba diving depths?
Every 10 meters of seawater adds about 1 bar (1 atm) of pressure. At the surface you experience 1 atm; at 10 m depth about 2 atm; at 30 m about 4 atm. This converter helps you switch these readings between bar and atm for dive planning.
What does kPa stand for and where is it used?
kPa stands for kilopascal, where 1 kPa = 1,000 pascals. It's used in meteorology for barometric pressure (standard sea-level pressure is about 101.325 kPa), in tire pressure gauges in some countries, and in scientific and HVAC applications. It relates to bar simply: 1 bar = 100 kPa.
Why do weather reports use hPa instead of kPa?
Weather services historically used millibars (mbar), and the hectopascal (hPa) is numerically identical to the millibar. Since 1 hPa = 0.1 kPa, a standard sea-level reading of 1,013 hPa equals 101.3 kPa. To convert an hPa reading to kPa with this tool, divide by 10 first.
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This converter is maintained by Aren Breur, the editor of ConvertAny.app. Aren builds fast, free browser-based tools that make everyday conversions simple without sign-ups or data collection. If you have feedback or a converter you would like added, reach out via the contact page or email aren2connect@gmail.com.