Pressure Converter: Pa, kPa, bar, atm, mmHg, Torr, psi and inHg

Quick conversion across units in physics, chemistry, geosciences and biology: gas laws (atm, bar, Pa, mmHg), hydrostatics and fluids (bar, kPa, mH₂O), barometric pressure and meteorology (hPa, mbar, inHg), pneumatics and engineering (psi, kgf/cm², bar) and clinical readings such as blood pressure (mmHg). The gauge reference solves the classic engineering need of turning a manometer reading into absolute pressure and back.

Start with the reference, using the Absolute / Gauge selector: absolute pressure is measured from a perfect vacuum, gauge pressure from the local atmosphere, which is what an ordinary manometer reads. Then type the value, pick the unit of the value and the unit of the result, and the page shows the general formula for that pair and, below it, the same operation with your number substituted. Unit conversion is identical under both references —one bar is 14.5038 psi no matter where the zero sits— so switching reference neither changes the result nor clears the field: what changes is the complementary pressure, the same pressure written under the other reference and in the unit of the result. That complement comes from P absolute = P gauge + P atmospheric, and the local atmosphere is editable: 1 atm by default, 1 bar one click away for the 'barg' convention, and any value of your own for work at altitude. 'Show all equivalents' opens the value across all 14 units at once, and the significant-figures selector switches between 6 and 10. A precision detail: mmHg and Torr are treated as distinct units —1 atm is exactly 760 Torr and 759.9998917 mmHg— something most converters overlook; at 6 figures both read 760, and it takes the 10-figure setting to see the difference.

The input must be a finite decimal, with optional scientific notation: an incomplete form such as 1e or text with letters is rejected whole instead of being trimmed. The local atmosphere must be a number greater than zero; when it is not, the converter says so on its own field and leaves the complementary pressure uncomputed, while the requested conversion is still shown. If the value implies a negative absolute pressure —below vacuum— a warning appears and the result is shown as well, because the arithmetic is right even though that pressure does not exist. Equivalents that fall outside the floating-point range appear as '—'. The tool converts units: it does not compute hydrostatic pressure or column height, and it uses the conventional values of mmHg, inHg and water column without correcting them for fluid temperature.

• Blood pressure · 120 mmHg gauge120 mmHg = 15.9987 kPa; as absolute, 117.324 kPa
• Tire · 32 psi gauge32 psi = 2.20632 bar; as absolute, 46.6959 psi
• Barometer · 1013.25 hPa1013.25 hPa = 1 atm = 29.9213 inHg
• mmHg is not Torr · 1 atm1 atm = 760 Torr = 759.9998917 mmHg (10 figures)