Pressure conversions

Pressure converter for SI and engineering units — pascals, kilopascals, megapascals, bars, millibars, pounds per square inch (psi), atmospheres, millimetres of mercury (mmHg), torr and inches of mercury (inHg).

10 units90 conversion tools📊 See comparison matrix →

Pa kPa MPa bar mbar psi atm mmHg Torr inHg

Pascal conversions

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The SI pressure unit — 1 newton per square metre

Pascal to Pound per Square Inch

1 Pa = 0.000145 psi

Pascal to Atmosphere

1 Pa = 9.8692e-6 atm

Pascal to Millimeter of Mercury

1 Pa = 0.007501 mmHg

Pascal to Torr

1 Pa = 0.007501 Torr

Pascal to Inch of Mercury

1 Pa = 0.0002953 inHg

kPa

Kilopascal conversions

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The engineering and tyre-pressure unit — 1 kPa = 1000 Pa

Kilopascal to Pascal

1 kPa = 1,000 Pa

Kilopascal to Megapascal

1 kPa = 0.001 MPa

Kilopascal to Bar

1 kPa = 0.01 bar

Kilopascal to Millibar

1 kPa = 10 mbar

Kilopascal to Pound per Square Inch

1 kPa = 0.145 psi

Kilopascal to Atmosphere

1 kPa = 0.009869 atm

Kilopascal to Millimeter of Mercury

1 kPa = 7.50062 mmHg

Kilopascal to Torr

1 kPa = 7.50062 Torr

Kilopascal to Inch of Mercury

1 kPa = 0.2953 inHg

MPa

Megapascal conversions

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Engineering high-pressure unit — 10 bar or 145 psi

Megapascal to Pascal

1 MPa = 1,000,000 Pa

Megapascal to Kilopascal

1 MPa = 1,000 kPa

Megapascal to Bar

1 MPa = 10 bar

Megapascal to Millibar

1 MPa = 10,000 mbar

Megapascal to Pound per Square Inch

1 MPa = 145.038 psi

Megapascal to Atmosphere

1 MPa = 9.86923 atm

Megapascal to Millimeter of Mercury

1 MPa = 7,500.62 mmHg

Megapascal to Torr

1 MPa = 7,500.62 Torr

Megapascal to Inch of Mercury

1 MPa = 295.3 inHg

bar

Bar conversions

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The everyday European engineering unit — 100 kPa

Bar to Pound per Square Inch

1 bar = 14.5038 psi

Bar to Atmosphere

1 bar = 0.9869 atm

Bar to Millimeter of Mercury

1 bar = 750.062 mmHg

Bar to Torr

1 bar = 750.062 Torr

Bar to Inch of Mercury

1 bar = 29.53 inHg

mbar

Millibar conversions

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The meteorology pressure unit — 100 pascals

Millibar to Pascal

1 mbar = 100 Pa

Millibar to Kilopascal

1 mbar = 0.1 kPa

Millibar to Megapascal

1 mbar = 0.0001 MPa

Millibar to Bar

1 mbar = 0.001 bar

Millibar to Pound per Square Inch

1 mbar = 0.0145 psi

Millibar to Atmosphere

1 mbar = 0.0009869 atm

Millibar to Millimeter of Mercury

1 mbar = 0.7501 mmHg

Millibar to Torr

1 mbar = 0.7501 Torr

Millibar to Inch of Mercury

1 mbar = 0.02953 inHg

psi

Pound per Square Inch conversions

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The US engineering and tyre-pressure unit — 6895 Pa

Pound per Square Inch to Pascal

1 psi = 6,894.76 Pa

Pound per Square Inch to Kilopascal

1 psi = 6.89476 kPa

Pound per Square Inch to Megapascal

1 psi = 0.006895 MPa

Pound per Square Inch to Bar

1 psi = 0.06895 bar

Pound per Square Inch to Millibar

1 psi = 68.9476 mbar

Pound per Square Inch to Atmosphere

1 psi = 0.06805 atm

Pound per Square Inch to Millimeter of Mercury

1 psi = 51.7149 mmHg

Pound per Square Inch to Torr

1 psi = 51.7149 Torr

Pound per Square Inch to Inch of Mercury

1 psi = 2.03602 inHg

atm

Atmosphere conversions

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The standard reference atmospheric pressure — 101,325 Pa

Atmosphere to Pascal

1 atm = 101,325 Pa

Atmosphere to Kilopascal

1 atm = 101.325 kPa

Atmosphere to Megapascal

1 atm = 0.1013 MPa

Atmosphere to Bar

1 atm = 1.01325 bar

Atmosphere to Millibar

1 atm = 1,013.25 mbar

Atmosphere to Pound per Square Inch

1 atm = 14.6959 psi

Atmosphere to Millimeter of Mercury

1 atm = 760 mmHg

Atmosphere to Torr

1 atm = 760 Torr

Atmosphere to Inch of Mercury

1 atm = 29.9213 inHg

mmHg

Millimeter of Mercury conversions

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The medical pressure unit — blood pressure and vacuum specs

Millimeter of Mercury to Pascal

1 mmHg = 133.322 Pa

Millimeter of Mercury to Kilopascal

1 mmHg = 0.1333 kPa

Millimeter of Mercury to Megapascal

1 mmHg = 0.0001333 MPa

Millimeter of Mercury to Bar

1 mmHg = 0.001333 bar

Millimeter of Mercury to Millibar

1 mmHg = 1.33322 mbar

Millimeter of Mercury to Pound per Square Inch

1 mmHg = 0.01934 psi

Millimeter of Mercury to Atmosphere

1 mmHg = 0.001316 atm

Millimeter of Mercury to Torr

1 mmHg = 1 Torr

Millimeter of Mercury to Inch of Mercury

1 mmHg = 0.03937 inHg

Torr

Torr conversions

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The vacuum-engineering unit — essentially equivalent to mmHg

1 Torr = 0.0001333 MPa

Torr to Bar

1 Torr = 0.001333 bar

Torr to Millibar

1 Torr = 1.33322 mbar

Torr to Pound per Square Inch

1 Torr = 0.01934 psi

Torr to Atmosphere

1 Torr = 0.001316 atm

Torr to Millimeter of Mercury

1 Torr = 1 mmHg

Torr to Inch of Mercury

1 Torr = 0.03937 inHg

inHg

Inch of Mercury conversions

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The US aviation altimeter unit — 3386 Pa per inch

Inch of Mercury to Pascal

1 inHg = 3,386.39 Pa

Inch of Mercury to Kilopascal

1 inHg = 3.38639 kPa

Inch of Mercury to Megapascal

1 inHg = 0.003386 MPa

Inch of Mercury to Bar

1 inHg = 0.03386 bar

Inch of Mercury to Millibar

1 inHg = 33.8639 mbar

Inch of Mercury to Pound per Square Inch

1 inHg = 0.4912 psi

Inch of Mercury to Atmosphere

1 inHg = 0.03342 atm

Inch of Mercury to Millimeter of Mercury

1 inHg = 25.4 mmHg

Inch of Mercury to Torr

1 inHg = 25.4 Torr

Tips for pressure conversions

1 bar = 100,000 Pa = almost 1 atmosphere. The bar is common in European weather and industry.

1 atmosphere = 101,325 Pa = 14.696 psi = 1013.25 mbar.

Car tyre pressure is typically 2.0–2.5 bar (29–36 psi, 200–250 kPa).

Blood pressure is measured in mmHg worldwide (e.g., 120/80 mmHg).

Common mistakes to avoid

Confusing absolute and gauge pressure — gauge is relative to atmospheric, absolute is from zero.

Mixing psi and bar when setting tyre pressures — roughly 14.5 psi per bar.

Using mmHg for engineering (should be Pa, kPa or bar).

Assuming standard atmosphere is exactly 1 bar — it's 1.01325 bar.

Learn about each unit

Full encyclopedia page for every pressure unit — definition, history, uses, tips.

What is a pascal?

What is a kilopascal?

kPa

What is a megapascal?

What is a pound per square inch?

psi

What is a atmosphere?

atm

What is a millimeter of mercury?

mmHg

What is a torr?

Torr

What is a inch of mercury?

inHg

Pressure conversion FAQ

Why is blood pressure measured in mmHg?

Early blood-pressure cuffs (from 1896) used mercury columns. The reading "120 mmHg" literally meant the blood pressure could support a 120 mm column of mercury. Even with modern electronic monitors, the mmHg unit remains the global medical standard for historical continuity.

What is the difference between absolute and gauge pressure?

Gauge pressure reads zero at atmospheric pressure (~101 kPa). Absolute pressure reads zero at a perfect vacuum. A tyre at "2 bar gauge" is at 3 bar absolute. Most everyday pressures (tyres, tanks) are given as gauge; scientific contexts use absolute.

Is 1 bar the same as 1 atmosphere?

Nearly, but not exactly. 1 bar = 100,000 Pa exactly. 1 standard atmosphere = 101,325 Pa. The difference (1.325%) is small but matters in precision work like scuba diving and aviation.