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Free Online Pressure Converter

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Pressure converter for every common unit — pascal, kilopascal, megapascal, bar, millibar, atmosphere, millimeter of mercury and pound per square inch. Type a value on either side; the result updates instantly. Useful for tire pressure (psi/bar), blood pressure (mmHg/kPa), weather charts (mbar/hPa), industrial hydraulics (MPa) and atmospheric calculations (atm). Everything runs in your browser — nothing uploaded.

Decimal places:

From (Atmospheric, Bar)

To (Imperial, Pound per square inch)

Supported units: Pascal (Pa), Kilopascal (kPa), Megapascal (MPa), Bar, Millibar (mbar), Atmosphere (atm), Millimeter of mercury (mmHg), Pound per square inch (psi).

Bar → Pound per square inch (psi)

Quick reference table

Bar	Pound per square inch (psi)
1 bar	14.5038 psi
2 bar	29.0075 psi
5 bar	72.5189 psi
10 bar	145.0377 psi
25 bar	362.5943 psi
50 bar	725.1887 psi
100 bar	1450.3774 psi

Pressure measurement contexts: medical, automotive, atmospheric, industrial

Different fields use different pressure units, and converting between them is a constant practical need. Medicine reports blood pressure in mmHg (a healthy reading is around 120/80 mmHg = 16.0/10.7 kPa). Automotive uses psi in the US and bar/kPa elsewhere — a 32 psi tire is 2.21 bar or 220 kPa. Meteorology and aviation use millibars or hectopascals (interchangeable: 1 mbar = 1 hPa = 100 Pa); standard sea-level pressure is 1013.25 mbar. Heavy industry — hydraulic systems, water-jet cutting, gas storage — works in megapascals (MPa) or bar; structural concrete strengths are quoted in MPa. Chemistry and gas-law problems use atmospheres (1 atm = 101,325 Pa exactly). This converter switches between all of these instantly.

Why mbar and hPa are the same; why mmHg and Torr are essentially equivalent

A few pressure units are commonly mistaken for distinct quantities. The millibar (mbar) and the hectopascal (hPa) are exactly the same: 1 mbar = 1 hPa = 100 Pa. Meteorology has historically used mbar; modern weather services (METAR, TAF) increasingly write hPa. Either name produces the same number. The millimeter of mercury (mmHg) and the Torr are also numerically identical to better than 0.0001 % — both equal 1/760 of a standard atmosphere. The tiny difference comes from the historical definition of mmHg (mercury column under standard gravity) versus the modern definition of Torr (exactly atm/760). For all practical purposes they can be used interchangeably; this converter treats mmHg as the canonical name.

Glossary

Pascal (Pa)

The pascal is the SI derived unit of pressure, defined as one newton per square meter (1 Pa = 1 N/m²). Named after Blaise Pascal. The Pa is too small for most everyday quantities — atmospheric pressure is about 101,325 Pa — so kilopascals (kPa) and megapascals (MPa) are used in practice. Common in fine-resolution scientific and engineering calculations.

Kilopascal (kPa)

A kilopascal equals 1,000 pascals. It is the everyday metric pressure unit for tire pressure outside the US (32 psi ≈ 220 kPa), atmospheric pressure (~101 kPa at sea level), HVAC duct pressure and blood-pressure readings reported in metric form (120/80 mmHg ≈ 16.0/10.7 kPa). The standard atmosphere equals 101.325 kPa exactly.

Megapascal (MPa)

A megapascal equals 1,000,000 pascals or 10 bar. It is the standard engineering unit for hydraulic systems, high-pressure gas, water-jet cutting, material yield strength and concrete compressive strength. Typical hydraulic systems run at 10–35 MPa; structural concrete reaches 20–80 MPa; high-pressure water jets exceed 400 MPa.

Bar

The bar is a non-SI metric pressure unit equal to exactly 100,000 Pa, very close to atmospheric pressure at sea level (1 atm = 1.01325 bar). Widely used in European engineering, automotive specs (turbo boost, fuel-rail pressure), tire pressure (2–3 bar typical), scuba diving and weather charts. Not part of SI but accepted for use with SI.

Millibar (mbar)

A millibar equals one thousandth of a bar, or 100 Pa. It is identical to the hectopascal (hPa) — meteorologists and weather services use both names interchangeably. Standard atmospheric pressure is 1013.25 mbar (= 1013.25 hPa). Surface weather charts, barometers and aircraft altimeters report station pressure in mbar/hPa.

Atmosphere (atm)

A standard atmosphere is defined as exactly 101,325 Pa (= 1.01325 bar = 760 mmHg = 14.696 psi). It represents average atmospheric pressure at sea level under standard conditions. Used in chemistry (gas-law problems), high-altitude aviation references and pressure-vessel ratings. Not the same as the technical atmosphere (at, ≈ 98,066.5 Pa) — that is a separate, rarely used unit.

Millimeter of mercury (mmHg)

A millimeter of mercury is the pressure exerted by a 1 mm column of mercury at standard gravity, equal to 133.322 Pa. It is the standard unit for blood pressure (120/80 mmHg) and for vacuum-system pressure in laboratory work. The Torr (named after Torricelli) is essentially the same unit — 1 Torr = 1/760 atm differs from 1 mmHg by less than 0.0001 %.

Pound per square inch (psi)

A pound-force per square inch equals 6,894.76 Pa. It is the dominant pressure unit in US automotive and engineering: tire pressure (32 psi = 2.21 bar), hydraulic systems (1,000–3,000 psi), bicycle tires (60–120 psi), municipal water (60 psi typical). Standard atmospheric pressure is 14.696 psi. The unit is sometimes split as psi-g (gauge, above atmospheric) and psi-a (absolute).

Related tools

psi to Bar

Convert psi to bar — 1 psi ≈ 0.06895 bar

Bar to psi

Convert bar to psi — 1 bar ≈ 14.504 psi

psi to kPa

Convert psi to kPa — 1 psi ≈ 6.895 kPa

mmHg to kPa

Convert mmHg to kPa — 1 mmHg ≈ 0.1333 kPa

atm to Bar

Convert atm to bar — 1 atm = 1.01325 bar exactly

kPa to MPa

Convert kPa to MPa — 1000 kPa = 1 MPa

mbar to Bar

Convert mbar to bar — 1000 mbar = 1 bar (mbar = hPa)

Length Converter

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