What is Pressure Converter?

Convert pressure between atmospheres, bar, millibar, pascal, hectopascal, kilopascal, megapascal, PSI, lb/ft², kN/m², kgf/cm², mmHg (torr), inHg, and water-column units, plus a standard-pressure-at-altitude lookup. Handy for HVAC work, structural and civil engineering, tire-pressure checks, weather readings, and lab calculations.

Type a number into any field and the sixteen others update at once. Conversions use 1 atm = 101,325 Pa exactly, 1 bar = 100,000 Pa, 1 hPa = 100 Pa, 1 PSI = 6,894.757 Pa, 1 lb/ft² = 47.880 Pa, 1 kN/m² = 1,000 Pa, 1 kgf/cm² = 98,066.5 Pa, and 1 mmHg (torr) = 133.322 Pa, plus water-column units (inH₂O, ftH₂O, cmH₂O, mmH₂O) for HVAC duct, plumbing, and gas-appliance specs. The fields are grouped into SI, practical, manometric, and water-column sections so you can scan straight to the unit you need. Switch the Gauge/Absolute toggle to read your value as either absolute pressure or as the difference above 1 atm, and pick 2 to 8 significant figures to keep the readout as tidy or as precise as you need. Quick-fill buttons load common scenarios like sea-level air, a car tire, blood pressure, scuba tank, or deep-sea depth, the Pressure-at-altitude panel returns the standard pressure for any elevation in metres or feet, and the Share link copies the exact conversion for a colleague.

How to use

1. Enter a pressure value in any unit field (e.g., 14.7 PSI).
2. All other pressure unit fields update simultaneously with equivalent values.
3. Copy whichever converted value you need.

When to use

• Setting tire pressure when the recommended PSI is printed but your gauge reads in bar or kPa.
• Translating mmHg from a blood-pressure cuff into kPa for international medical notes.
• Sizing pneumatic equipment where the spec sheet is in bar but local gauges read PSI.

Result

Convert standard atmospheric pressure (1 atm) to see it equals 101,325 Pa, 1.01325 bar, 14.696 PSI, and 760 mmHg.

FAQ

Is mmHg the same as torr?

Practically yes. Both equal the pressure of a 1 mm column of mercury at standard gravity, which is 133.322 Pa. The torr was redefined in 1954 to be exactly 1/760 atm, leaving a difference too small to matter outside a national metrology lab.

Why is bar so close to atm but not equal?

The bar was defined as 100,000 Pa for round numbers. One atmosphere (101,325 Pa) is 1.325% bigger. Weather charts use hPa (1 hPa = 1 mbar) because the typical sea-level reading lands between 980 and 1040 mbar, which is easier to read than 0.98 atm.

Should I use absolute or gauge pressure for tire readings?

Tire labels and gauges report gauge pressure: the difference above local atmosphere. A tire labeled 32 PSI actually holds about 46.7 PSI absolute at sea level. Flip the Gauge/Absolute toggle above the input grid to switch how this tool interprets the number you enter, so the same 32 PSI can be displayed either as 32 (gauge) or 46.7 (absolute) depending on what you need.

What's the difference between inHg and mmHg?

Both measure the height of a mercury column, only in different rulers. 1 inHg equals 25.4 mmHg, so US weather reports of 29.92 inHg are the same atmospheric pressure as the European 760 mmHg or 1013.25 hPa.

How does pressure relate to altitude?

Atmospheric pressure drops about 12 hPa per 100 m of elevation near sea level. Denver at 1,610 m sees roughly 837 hPa instead of 1,013 hPa. That's why bagged snacks puff up on flights and why high-altitude recipes need adjustments. Open the Pressure-at-altitude panel above, enter an elevation in metres or feet, and it returns the standard pressure there using the ICAO/ISA troposphere model — then push that value straight into the converter.

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