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Converters

Pressure Converter

Convert between pascals, bar, PSI, atmospheres, mmHg, and mmH₂O — for tire pressures, weather reports, diving, and engineering.

Pascals (Pa)1
Kilopascals (kPa)0.001
Bar0.00001
Atmospheres (atm)0.00001
PSI0.000145
mmHg (torr)0.007501
mmH₂O0.101972

Anchored conversions from Pascals (Pa) use exact internationally agreed factors. Everything is computed locally, instantly.

Gauge, Absolute and the Unit That Keeps Confusing

bar, psi, kPa and atmospheres all measure the same quantity, but two reference points exist: gauge pressure (relative to ambient, what a tire gauge reads) and absolute pressure (relative to vacuum). A tire at 2.5 bar gauge is about 3.5 bar absolute — and weather reports, scuba tanks and engineering specs do not always state which they mean. The unit "mmHg" survives from mercury manometers (760 mmHg = 1 atm exactly in the classic definition), which is why blood pressure still uses it.

How the Conversion Works

  1. Enter a pressure in any unit; all others convert at once, anchored on the pascal.
  2. The SI anchor is exact: 1 bar = 100,000 Pa, 1 atm = 101,325 Pa (exact by definition).
  3. Tire, diving, and weather context hints translate the numbers into familiar regimes.
  4. Copy any individual result or the full table.
Formula & Technical Standard
1 bar = 10⁵ Pa · 1 atm = 101,325 Pa (exact) · 1 psi = 6,894.757293 Pa (exact) · 1 mmHg ≈ 133.322 Pa.

Conversion Example

Car tire pressure
Input: 2.2 bar
Output: 31.9 psi
European cars quote bar; US gauges read psi. This is the classic garage conversion.
Blood pressure unit origin
Input: 120 mmHg
Output: ≈ 16 kPa · 0.158 atm
Medicine still uses mmHg (torr) — converting puts it in SI terms.

Common Questions

What is the difference between bar and atm?

They are close (1 bar vs 1.01325 atm) but not equal. Weather maps use hPa (=mbar), while diving uses bar; the tool keeps both exact.

Is gauge pressure the same as absolute?

No. Gauge pressure is relative to atmospheric (a tire gauge reads 0 at ambient). The factors here convert like-for-like; add ~1 bar for absolute.

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