Pressure Converter
Convert between pascals, bar, PSI, and atmospheres.
Quick reference
- 1 atmosphere = 14.696 psi = 1.01325 bar
- 1 atmosphere = 101,325 Pa = 760 mmHg
- 1 bar = 100,000 Pa ≈ 14.5 psi
- Typical car tire ≈ 32 psi ≈ 2.2 bar
About this converter
Tire pressure, weather reports, and engineering specs all lean on different pressure units depending on the field, and this converts between the SI unit (pascals), the common practical units (bar, PSI, atmospheres), and mmHg, which is still how barometric readings and blood pressure get reported.
None of these units is technically wrong, they're the same physical quantity (force per area) that got standardized separately by different industries at different points in history. PSI stuck around in US customary contexts like tires and plumbing, bar took over in Europe and diving, atm became chemistry's reference point, and pascals are what physics actually calculates with. Once the tools and textbooks in a field were built around one, there wasn't much reason to switch.
Frequently asked questions
- What's a typical car tire pressure in these units?
- Around 32 psi for a passenger car, which works out to roughly 2.2 bar or 220 kPa. That's why you'll see three different numbers depending on where the tire gauge was made.
- What's mmHg used for?
- Blood pressure readings ("120 over 80" is 120 mmHg over 80 mmHg) and, historically, barometers. It sticks around in medicine mostly because decades of reference ranges were already built around it.
- Is bar close enough to atm to treat them as the same?
- Close, but not identical, 1 bar is about 0.987 atm. Fine for a rough estimate, not fine if you're doing a chemistry calculation that expects atm exactly.