Pressure converter

Convert psi to bar, bar to psi, kPa, atm, hPa, mmHg and inHg for tyre, weather and blood pressure readings. The factor chain identifies exact definitions and the conventional approximate inHg model.

By Admin Drafted with AI writing toolsUpdated 2 November 2026Checked examples: 4

Converted value

bar

Significant figures: 12; Nearest, ties away from zero

Conversion: 32 psi ≈ 2.206322 bar
Conversion factor: 0.0689475729317
Exactness: Exact definitions, repeating decimal

32 psi is about 2.206322 bar. One pound-force per square inch is about 0.06894757 bar.

The same amount counted in each unit

32 psi in every Pressure unit Rows: 11

Unit	Value	Definition
pascal (Pa)	220,632.2	Base unit
hectopascal (hPa)	2,206.322	1 hPa = 100 Pa, exact
kilopascal (kPa)	220.6322	1 kPa = 1,000 Pa, exact
megapascal (MPa)	0.2206322	1 MPa = 1,000,000 Pa, exact
bar	2.206322	1 bar = 100,000 Pa, exact
standard atmosphere (atm)	2.177471	1 atm = 101,325 Pa, exact
pound-force per square inch (psi)	32	1 psi = 4.4482216152605/0.00064516 Pa, exact
millimetre of mercury (mmHg)	1,654.878	1 mmHg = 133.322387415 Pa, exact
torr (Torr)	1,654.878	1 Torr = 101,325/760 Pa, exact
inch of mercury (inHg)	65.15265	1 inHg = 3,386.389 Pa, approximate (Conventional value at 0 °C)
kilogram-force per cm² (kgf/cm²)	2.249823	1 kgf/cm² = 98,066.5 Pa, exact

How it's calculated S

Convert pound-force per square inch to pascal
$32\ \text{psi} \times \tfrac{4.4482216152605}{0.00064516}\ \tfrac{\text{Pa}}{\text{psi}} = 220{,}632.233381\ \text{Pa}$
1 psi = 4.4482216152605/0.00064516 Pa, exact
Convert pascal to bar
$220{,}632.233381\ \text{Pa} \div 100{,}000\ \tfrac{\text{Pa}}{\text{bar}} = 2.20632233381\ \text{bar}$
1 bar = 100,000 Pa, exact
Combined factor
$1\ \text{psi} = \frac{\tfrac{4.4482216152605}{0.00064516}}{100{,}000}\ \text{bar} \approx 0.0689475729317\ \text{bar}$
Both units are defined exactly, but the converted value is a repeating decimal; it is shown to 12 significant figures.

About the pressure converter

Each pressure unit is a fixed number of pascals (newtons per square metre). The bar is exactly 100,000 Pa, the standard atmosphere 101,325 Pa and the torr 1/760 atm. The psi, one pound-force per square inch, is about 6,894.757 Pa, fixed exactly by the 1959 pound, standard gravity (9.80665 m/s²) and the 25.4 mm inch.

The default converts a 32 psi tyre pressure to approximately 2.2063 bar. Weather maps use hectopascals (1 hPa = 1 mbar; standard sea-level pressure is 1,013.25 hPa), and blood pressure is recorded in millimetres of mercury.

Gauge and absolute readings convert with the same factor but are not interchangeable: a tyre gauge shows pressure above the surrounding air, so 32 psi on the gauge is about 46.7 psi absolute when ambient pressure is one standard atmosphere. The inch of mercury uses the conventional value at 0 °C and is marked approximate.

How to convert psi to bar

Divide psi approximately by 14.5038, or multiply approximately by 0.0689476: a 32 psi tire reading is approximately 2.2063 bar. A psi is one pound-force per square inch, about 6,894.757 Pa, and a bar is exactly 100,000 Pa. The same factor applies to gauge and absolute readings.

The psi factor follows from three exact definitions: the 0.45359237 kg pound, standard gravity of 9.80665 m/s² and the 0.0254 m inch. Dividing 4.4482216152605 N by 0.00064516 m² gives approximately 6,894.757293 Pa (NIST SP 811, Appendix B.9).

How to convert bar to psi

Multiply bar approximately by 14.5038. Rounded tire-pressure equivalents in both units:

2.0 bar ≈ 29.01 psi
2.2 bar ≈ 31.91 psi
2.5 bar ≈ 36.26 psi
30 psi ≈ 2.07 bar
35 psi ≈ 2.41 bar

Unless explicitly identified as exact, decimal conversions in the prose are rounded approximations. Unit conversion preserves the pressure reference of the input.

psi to kPa, MPa and hPa

Multiply psi by 6.894757 for kilopascals: 32 psi is 220.63 kPa, and 1 kPa is 0.145038 psi. Because 1 bar is exactly 100 kPa, kPa ÷ 100 gives bar, and 1 MPa is 10 bar or 145.04 psi.

Weather maps use hectopascals, which equal millibars: 1 hPa = 1 mbar = 100 Pa. The standard atmosphere is exactly 101,325 Pa, which is 1,013.25 hPa, 1.01325 bar, 14.696 psi or 760 Torr.

Blood pressure and other mercury units

Blood pressure is recorded in millimeters of mercury. A conventional mmHg is 133.322387415 Pa, so a reading of 120/80 mmHg is 16.0/10.7 kPa.

A torr is exactly 1/760 of a standard atmosphere, approximately 133.322368 Pa, so 760 Torr is exactly 1 atm. The torr and the mmHg differ by about 0.14 parts per million, so these remain distinct units when greater precision is required.

US weather reports and aircraft altimeters use inches of mercury: 29.92 inHg is 1,013.21 hPa, the standard altimeter setting.

The inHg factor is the conventional 3,386.389 Pa for mercury at 0 °C (NIST SP 811, Appendix B.8), so inHg results are approximate.

Pressure conversion chart

Long decimals are rounded to six places; the inHg row uses the conventional factor.

Value	From	To	Converted pressure
32	psi	bar	2.206322
2.5	bar	psi	36.259434
1	atm	hPa	1013.25
760	Torr	atm	1
120	mmHg	kPa	15.998686
29.92	inHg	hPa	1013.207589

Gauge vs absolute pressure

A tire or compressor gauge reads pressure above the surrounding air (psig). Absolute pressure (psia) counts from a vacuum, so when ambient pressure is one standard atmosphere, psia ≈ psig + 14.7. A gauge reading of 0 psig means absolute pressure equals local ambient pressure, about 14.7 psia under that assumption.

Converting units keeps whichever reference the reading had, so 32 psig becomes 2.2063 bar gauge. Add the local air pressure only when a formula, such as the ideal gas law, needs absolute pressure: 32 psig is about 46.7 psia when ambient pressure is one standard atmosphere.

Common mistakes

Treating bar and atm as equal. 1 atm is 1.01325 bar, about a 1.3% gap that matters in calibration work.
Mixing gauge and absolute values. Comparing a psig reading with a psia rating is off by about 14.7 psi when ambient pressure is one standard atmosphere.
Confusing hPa with kPa. 1,013 hPa is 101.3 kPa; the prefixes differ by a factor of 10.
Reading kgf/cm² as a weight. One kilogram-force per square centimeter is a pressure of 98.0665 kPa, 0.980665 bar or 14.22 psi.

For one direction at a time, use psi to bar, bar to psi, psi to kPa or kPa to psi. The blood pressure category calculator classifies a reading, and the air pressure at altitude calculator shows how pressure falls with height.

Worked examples

32 psi tyre pressure in bar

Value: 32 psi
From: pound-force per square inch (psi)
To: bar

Converted value: 2.2063223338 bar

Checked against: 1 psi = 4.4482216152605 N ÷ (0.0254 m)² (NIST SP 811 App. B); 32 psi = 8896443230521/4032250000000 bar

1 atm in psi

Value: 1 atm
From: standard atmosphere (atm)
To: pound-force per square inch (psi)

Converted value: 14.6959487755 psi

Checked against: 101325 Pa ÷ 6894.757293168… Pa

760 torr is 1 atm

Value: 760 Torr
From: torr (Torr)
To: standard atmosphere (atm)

Converted value: 1 atm
Exactness: Exact

Checked against: 1 torr = 101325/760 Pa by definition (NIST SP 811 App. B)

1 inHg (conventional value)

Value: 1 inHg
From: inch of mercury (inHg)
To: pascal (Pa)

Converted value: 3,386.389 Pa
Exactness: Approximate

Checked against: NIST SP 811 App. B.9: inch of mercury (0 °C) = 3.386389 E+03 Pa

Questions

How do I convert psi to bar?

Divide approximately by 14.5038, or multiply approximately by 0.0689476. A bar is exactly 100,000 Pa and a psi approximately 6,894.757 Pa, so 1 bar ≈ 14.5038 psi. A 32 psi tyre reading is approximately 2.2063 bar, and 2.5 bar is approximately 36.26 psi.

Is 1 bar the same as 1 atmosphere?

No, though they are about 1.3% apart. The bar is exactly 100,000 Pa, while the standard atmosphere is exactly 101,325 Pa, which is 1.01325 bar, approximately 14.696 psi or approximately 760 mmHg. The atmosphere was set to match average sea-level air pressure, which is why weather charts centre on 1,013.25 hPa.

What is the difference between psig and psia?

psig is gauge pressure, measured relative to the surrounding air; psia is absolute pressure, measured from a vacuum. When ambient pressure is one standard atmosphere, psia is approximately psig + 14.696. A gauge reading of 0 psig means its absolute pressure equals local ambient pressure, approximately 14.7 psia under that assumption. Unit conversion does not change the pressure reference, so keep input and output the same kind.

Are mmHg and torr the same?

Almost. A torr is exactly 1/760 of a standard atmosphere, approximately 133.322368 Pa; the converter uses 133.322387415 Pa for conventional millimetres of mercury. They differ by about 0.14 parts per million. In the 120/80 example, both units round to 16.0/10.7 kPa at the displayed precision. They remain distinct units when greater precision is required.

How do I convert inches of mercury to hPa?

Multiply approximately by 33.8639: 29.92 inHg is approximately 1,013.2 hPa, the rounded representation of the standard altimeter setting in US aviation. This converter uses the conventional inch of mercury at 0 °C, 3,386.389 Pa (NIST SP 811), and marks results that use it as approximate because mercury density changes with temperature.

About this calculator

\begin{gathered} x_{\text{to}} = x_{\text{from}} \times \dfrac{f_{\text{from}}}{f_{\text{to}}} \\ f = \text{one unit expressed in } \text{Pa} \end{gathered}

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Checked against references

This calculator includes 4 worked examples with independently sourced answers. They run in the test suite, and you can run them here too.

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