Pressure Converter
Convert between bar, PSI, pascals, kilopascals, atmospheres, mmHg, inHg, torr and other pressure units. This tool is useful for tyre pressures, weather pressure, engineering checks, science, diving context and quick metric-to-imperial comparisons. Enter a value in any unit and every other pressure unit updates in real time.
Convert pressure
Choose any input box, enter a pressure, and the calculator converts it through pascals as the base SI unit. This keeps Pa, kPa, MPa, bar, PSI, atm, mmHg, inHg and water-column units consistent across the page.
Quick references
Full conversion table
Enter a pressure value above to see all conversions.
Real-world pressure guide
Common pressures you might encounter in everyday life.
Tyre pressure quick-reference
Common tyre pressures in PSI and bar — always check your vehicle handbook for exact values.
Conversion formulas
How it works
This converter uses pascals as the central base unit because the pascal is the SI unit of pressure. When you enter a value, the calculator first converts that pressure into pascals, then converts the pascal value into every other unit shown on the page.
Pressure is force per unit area, so different pressure units often come from different measurement systems. For example, PSI is pounds per square inch, bar is common for tyres and engineering, mmHg is common in blood pressure, and hectopascals or millibars are common in weather reporting.
Formula used
For most pressure conversions, the calculator uses this two-step formula:
converted value = value in Pa ÷ Pa factor of target unit
Common factors include: 1 bar = 100,000 Pa, 1 kPa = 1,000 Pa, 1 MPa = 1,000,000 Pa, 1 atm = 101,325 Pa, 1 PSI ≈ 6,894.757 Pa, 1 mmHg ≈ 133.322 Pa and 1 inHg ≈ 3,386.389 Pa.
Worked example
Example: convert 32 PSI to bar
A common car tyre pressure can be converted from PSI to bar using the PSI-to-pascal factor first.
220,632.224 Pa ÷ 100,000 = 2.2063 bar
So, 32 PSI is about 2.21 bar.
Example: convert 1 atm to kPa
A standard atmosphere is defined as 101,325 Pa.
101,325 Pa ÷ 1,000 = 101.325 kPa
So, 1 atm is 101.325 kPa.
Common mistakes
Confusing PSI and bar
PSI and bar are very different scales. For example, 32 PSI is about 2.21 bar, not 32 bar.
Mixing absolute and gauge pressure
Some pressure readings are gauge pressure and others are absolute pressure. This converter only converts units; it does not add or remove atmospheric pressure.
Using tyre pressure as a universal value
Tyre pressures vary by vehicle, load, tyre size and temperature. Always check the vehicle handbook or tyre placard.
Rounding too early
For engineering, lab or safety-related work, keep more significant figures during calculation and round only the final result.
Common questions
How many PSI are in 1 bar? ⌄
How many kPa are in 1 bar? ⌄
What does PSI mean? ⌄
Is mmHg only used for blood pressure? ⌄
Sources, assumptions and disclaimer
This converter is intended for general everyday use, tyre-pressure comparison, study and quick engineering checks. It is not a substitute for calibrated instruments, manufacturer guidance, safety procedures or professional engineering judgement.
- Base unit: conversions are handled through pascals, the SI unit of pressure.
- Tyre pressure: tyre examples are broad references only. Always follow the tyre placard, vehicle handbook or manufacturer data.
- Medical context: blood pressure examples are for unit conversion context only and are not medical advice.
- Weather pressure: hectopascals and millibars are commonly used in weather reporting and are numerically equivalent.
- Gauge versus absolute pressure: this calculator converts units only. It does not determine whether a measurement is gauge pressure or absolute pressure.
- Safety disclaimer: do not rely on this page alone for pressure vessels, gas cylinders, scuba equipment, tyres, boilers, hydraulics or other safety-critical systems.