Metric and imperial pressure conversions
Pressure Converter
Convert pascals, kilopascals, bar, psi and atmospheres instantly with our free online pressure converter. No signup required, works offline.
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How to Convert Pressure Units
Pressure conversions matter for tyre inflation, scuba diving, weather forecasting, engineering and HVAC work. Different fields use different units: mechanics use psi and bar, scientists use pascals and atmospheres, and meteorologists worldwide use hectopascals (equivalent to millibars). This converter handles the five most common units and gives results that match industry-standard equipment.
Key Pressure Conversion Formulas
1 bar = 100 kPa = 14.5038 psi
1 atm = 101.325 kPa (standard atmosphere at sea level)
1 psi = 6.89476 kPa
1 kPa = 0.145 psi
The pascal is the SI unit of pressure, defined as one newton per square metre. Because one pascal is a very small amount of pressure, everyday values are quoted in kilopascals (kPa) or bar. One bar is defined as exactly 100,000 pascals, very close to normal atmospheric pressure at sea level, which is why weather and diving use it.
Common Pressure Conversions
| Pressure | Equals | Real-world reference |
|---|---|---|
| 1 bar | 100 kPa / 14.50 psi | Typical car tyre pressure (about 2.2 bar) is 32 psi |
| 1 atmosphere (atm) | 101.325 kPa | Standard sea-level air pressure |
| 1 psi | 6.895 kPa | Bicycle tyres run at 60-100 psi |
| 1 kPa | 0.145 psi | Meteorologists report pressure in hPa, equal to 0.1 kPa |
| 2.4 bar | 34.8 psi | Common modern car tyre pressure |
| 1 MPa | 10 bar / 145 psi | Used in engineering; equals 1,000 kPa |
Practical Uses for a Pressure Converter
- Tyre pressure: Car manuals quote pressure in bar or psi depending on market; correct inflation saves fuel and tyres
- Scuba diving: Divers track tank pressure in bar; understanding atmospheres of depth is essential for dive safety
- Weather: Reading international forecasts that report pressure in hectopascals or millibars instead of inches of mercury
- HVAC and plumbing: System pressures are specified in psi, bar or kPa depending on the manufacturer and region
- Engineering: Converting design pressures between units when working with international specifications
Understanding the Units
Pressure measures force applied over an area. The pascal is the SI unit (1 N/m²), but it is too small for practical use, so engineers and scientists use kilopascals and megapascals. Bar was adopted because it is close to average atmospheric pressure at sea level. PSI (pounds per square inch) is the standard in the United States and remains common in automotive work worldwide. The standard atmosphere (atm) is defined as 101,325 Pa and is used in chemistry and diving. All five units in this converter are linked by exact conversion factors, so results are consistent whichever direction you convert.
Frequently Asked Questions
How many psi are in a bar?
One bar equals 14.5038 psi. To convert bar to psi, multiply by 14.5. To convert psi to bar, divide by 14.5. Use our pressure converter for instant results.
What is the normal tyre pressure in bar and psi?
A typical family car runs at 2.2 to 2.5 bar, which is 32 to 36 psi. Check the sticker inside your driver's door for the exact figure for your vehicle.
Is 1 bar the same as 1 atmosphere?
Not exactly. One bar is 100,000 pascals, while one standard atmosphere is 101,325 pascals. The difference is about 1.3%, so they are often treated as equivalent in everyday use but not in precise calculations.
How do I convert kPa to psi?
Divide the value in kPa by 6.895 to get psi. For example, 240 kPa (a common tyre pressure) divided by 6.895 is about 34.8 psi.
What is the difference between gauge pressure and absolute pressure?
Gauge pressure measures pressure relative to atmospheric pressure (tyre gauges read this), while absolute pressure includes atmospheric pressure. At sea level, absolute pressure is gauge pressure plus 1 atm (101.325 kPa).
Does the pressure converter work offline?
Yes. All conversions are computed locally in your browser with exact factors, so the tool works offline and no data ever leaves your device.