Pressure Converter
Convert pressure between pascals, bar, psi, atmospheres, mmHg and more, with a complete table of your value in every unit.
Pressure Converter — input your values
What does this conversion calculator do?
The pressure converter covers the units used in meteorology, diving, engineering and everyday life: pascals and its multiples, bar and millibar, atmospheres, psi, and millimeters or inches of mercury.
All conversions pass through the pascal as the reference base. Note that hPa and mbar are numerically equal, and standard sea-level atmospheric pressure is 1,013.25 hPa = 1 atm = 14.696 psi.
Formula and variables
1 atm = 101,325 Pa exactly; 1 bar = 100,000 Pa; 1 psi = 6,894.757 Pa.
| Symbol | Meaning |
|---|---|
| factor(from) | How many pascals one 'from' unit equals |
| factor(to) | How many pascals one 'to' unit equals |
Worked example
Convert 2 bar into psi.
- 2 bar × 100,000 = 200,000 Pa.
- 200,000 Pa ÷ 6,894.757293 = 29.00755 psi.
Answer: 2 bar ≈ 29.01 psi.
Tips and common mistakes
Tips
- Tire pressures are commonly quoted in psi (US/UK), bar (Europe) or kPa (Asia) — check which unit your vehicle's manual uses.
- Weather reports use hectopascals or millibars interchangeably: 1,013 hPa = 1,013 mbar is standard sea-level pressure.
- An atmosphere is a handy reference: 1 atm ≈ 1.013 bar ≈ 14.696 psi.
- Scuba divers add 1 atm of pressure for every 10 meters of depth — 30 m of seawater is about 4 atm total.
Common mistakes to avoid
- Confusing gauge pressure with absolute pressure — most tire gauges read gauge pressure, which excludes atmospheric pressure.
- Assuming bar and psi are close: 1 bar is about 14.5 psi, a factor people often misremember.
- Using mmHg instead of inHg in US contexts — they differ by a factor of 25.4.
Pressure Converter — frequently asked questions
How many psi is 1 bar?
One bar equals approximately 14.5038 psi. So a typical 2.4 bar tire pressure is about 34.8 psi.
What is standard atmospheric pressure?
Standard sea-level pressure is 101,325 Pa, or 1,013.25 hPa, 1 atm, 1.01325 bar, or 14.696 psi.
What does psi stand for?
Pounds per square inch — the force in pounds applied to each square inch of surface. It is the common pressure unit in the US.
What is the difference between hPa and mbar?
None — 1 hPa equals 1 mbar exactly. Meteorologists historically used millibars and now use the SI unit hectopascals.
How is blood pressure measured?
In millimeters of mercury (mmHg): a reading like 120/80 means systolic pressure of 120 mmHg over diastolic of 80 mmHg.
What is gauge pressure?
Gauge pressure is pressure measured relative to the atmosphere. Absolute pressure adds the atmospheric pressure — for example, 30 psi gauge is about 44.7 psi absolute.