Pressure Converter — Free
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Tyre gauges ask for psi or bar, weather reports speak hectopascals, scuba computers count bar, and medicine measures blood pressure in millimeters of mercury. Enter a value in any of the eight units and all the others convert together.
How it works
- 1
Find the unit on your gauge
Bar, psi, kPa, mmHg — every common label is here.
- 2
Type the reading
The other seven units recalculate as you type.
- 3
Sanity-check the size
Sea-level atmosphere and a typical tyre sit in the guide below.
About this tool
Eight units, one physical thing
Pressure is force spread over area. The pascal is the SI answer — one newton per square meter, small enough that daily life uses thousandfold multiples. The bar (100,000 Pa) approximates one atmosphere, which was later pinned to exactly 101,325 Pa, and millimeters of mercury descend from the height a column of mercury stands at — the original barometer reading.
Reference points worth knowing
Sea-level air pressure is about 1.013 bar, 1013 hPa, or 14.7 psi. A car tyre runs 2.2–2.5 bar (32–36 psi). Weather maps label low pressure around 980 hPa and strong highs near 1030 hPa. A scuba tank holds 200-plus bar of compressed air.
Frequently asked questions
How many psi is a bar?
One bar is 14.5038 psi. Car manuals that quote 2.4 bar mean roughly 35 psi.
Are hectopascals and millibars the same?
Yes — 1 hPa equals 1 millibar exactly. Weather services switched to hectopascals when the pascal became standard; the numbers did not move.
What is the mmHg unit used for?
Blood pressure and vacuum measurements. One mmHg is 133.322 Pa, and the torr used in laboratories matches it to within a few parts per million.