What is tyre pressure in bar vs psi?

Typical car tyre pressure is 2.0–2.5 bar, which is equivalent to 29–36 psi. Always check your vehicle’s door placard or owner’s manual for the recommended inflation pressure.

Pressure Converter

Pa · kPa · MPa · bar · psi · atm · mmHg · torr

Convert pressure units instantly between SI and imperial systems. Supports pascals, bar, psi, atmospheres, mmHg, torr, and more. Free online tool — no signup required.

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Key Formulas

1 atm = 101,325 Pa
1 bar = 14.5038 psi
1 mmHg = 133.322 Pa

Formula: 1 Pa = 1 Pa

Conversion Table

Unit	Name	Value

About Pressure Units

Pressure is defined as force per unit area. The SI unit of pressure is the pascal (Pa), equal to one newton per square metre. In everyday life you encounter pressure in tyre gauges (psi or bar), weather reports (mbar or hPa), and blood pressure readings (mmHg). Each field has adopted its own preferred unit, making conversion essential for engineers, medics, and scientists.

The bar and psi are the two most widely used non-SI units. One bar is very close to one atmosphere (atm), while one atmosphere is exactly 101,325 Pa. In medicine and meteorology, millimetres of mercury (mmHg) and torr remain the standard. Industrial and hydraulic systems often use MPa (megapascals) or kgf/cm² for high-pressure applications such as hydraulic presses and SCUBA cylinders.

Quick Reference — Common Pressure Conversions

1 atm

101,325 Pa

= 101.325 kPa

1 bar

14.5038 psi

= 100,000 Pa

1 psi

6,894.76 Pa

= 0.0689476 bar

1 mmHg

133.322 Pa

= 0.133322 kPa

1 kPa

0.145038 psi

= 1,000 Pa

1 MPa

145.038 psi

= 10 bar

1 torr

133.322 Pa

≈ 1 mmHg

1 inHg

3,386.39 Pa

= 0.491154 psi

1 kgf/cm²

98,066.5 Pa

= 14.2233 psi

1 mbar

100 Pa

= 0.0145 psi

Worked Examples

1 atm to Pa

Multiply by 101,325. One standard atmosphere is defined as exactly 101,325 pascals.

1 atm = 101,325 Pa

30 psi to bar

Multiply psi by 0.0689476. Typical car tyre pressure of 30 psi converts as follows:

30 × 0.0689476 ≈ 2.068 bar

760 mmHg to kPa

Multiply mmHg by 0.133322. Standard atmospheric pressure in mmHg is 760.

760 × 0.133322 ≈ 101.32 kPa

100 kPa to atm

Divide kPa by 101.325. This is slightly less than one standard atmosphere.

100 ÷ 101.325 ≈ 0.9869 atm

Where Pressure Conversion Is Used

Tyres & Automotive

Tyre pressure gauges show psi in the US and bar in Europe. Converting keeps your car safe regardless of where you fill up.

Weather & Meteorology

Barometric pressure is reported in hPa (hectopascals) or mbar. Storm systems bring low pressure; high pressure means fair weather.

Medical & Blood Pressure

Sphygmomanometers measure blood pressure in mmHg. Normal adult blood pressure is about 120/80 mmHg (16/10.7 kPa).

Engineering & Hydraulics

Hydraulic systems typically operate at 150–350 bar. Engineers convert between bar, MPa and psi when specifying components.

SCUBA Diving

Dive cylinders are rated in bar (200–300 bar). Depth pressure increases by ~1 bar per 10 m of water depth.

Industrial Processes

Chemical plants and gas pipelines use kPa or MPa for process pressures, requiring accurate conversion for safety margins.

Mental Math Tips

bar to psi

1 bar ≈ 14.5 psi
Multiply bar × 14.5

atm to bar

1 atm ≈ 1.013 bar
Very nearly equal

kPa to psi

kPa ÷ 6.895 ≈ psi
Or × 0.145

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Frequently Asked Questions

A pascal (Pa) is the SI base unit of pressure, defined as one newton per square metre (N/m²). It is named after mathematician Blaise Pascal. Everyday pressures are often expressed in kilopascals (kPa) because a single pascal is very small — standard atmospheric pressure is 101,325 Pa.

Bar and psi are both pressure units but from different measurement systems. One bar equals 14.5038 psi. Bar is used in metric countries for tyre pressure and industrial gauges, while psi (pounds per square inch) is common in the US and UK for the same applications.

Blood pressure is measured in millimetres of mercury (mmHg) because early sphygmomanometers used a mercury column to measure pressure. Normal adult blood pressure is about 120/80 mmHg. One mmHg equals 133.322 Pa. The unit persists in clinical medicine worldwide.

Typical car tyre pressure is 2.0–2.5 bar, which is equivalent to 29–36 psi. Always check your vehicle\u2019s door placard or owner\u2019s manual for the recommended inflation pressure, as it varies by vehicle and tyre size.

One standard atmosphere (1 atm) is exactly 101,325 Pa, which equals 101.325 kPa, 1.01325 bar, or 14.696 psi. It represents the average atmospheric pressure at sea level and is used as a reference pressure in many scientific and engineering calculations.

To convert psi to bar, multiply by 0.0689476. For example, 30 psi × 0.0689476 ≈ 2.068 bar. To go the other way, multiply bar by 14.5038 to get psi. Our converter above handles both directions instantly.

A torr is a unit of pressure named after Evangelista Torricelli. It is defined as exactly 1/760 of a standard atmosphere, making 1 torr ≈ 133.322 Pa. For most practical purposes, 1 torr ≈ 1 mmHg, though they differ very slightly. Torr is commonly used in vacuum science and laboratory settings.

All Pressure Conversions

Common

psi → bar bar → psi psi → kPa kPa → psi bar → kPa kPa → bar atm → psi psi → atm atm → bar bar → atm

Metric (SI)

MPa → kPa kPa → MPa kPa → Pa Pa → kPa MPa → Pa Pa → MPa bar → Pa Pa → bar mbar → Pa Pa → mbar mbar → bar bar → mbar kPa → MPa MPa → bar

Atmospheric

atm → Pa Pa → atm atm → kPa kPa → atm atm → bar bar → atm atm → psi psi → atm atm → mmHg mmHg → atm atm → inHg inHg → atm

Medical & Weather

mmHg → Pa Pa → mmHg mmHg → kPa kPa → mmHg mmHg → psi psi → mmHg inHg → kPa kPa → inHg inHg → Pa inHg → psi mbar → kPa mbar → mmHg torr → Pa torr → mmHg

Engineering & Industrial

psi → MPa MPa → psi bar → MPa MPa → bar kgf/cm² → psi psi → kgf/cm² kgf/cm² → bar bar → kgf/cm² kgf/cm² → kPa kPa → kgf/cm² kgf/cm² → MPa MPa → kgf/cm² psi → Pa MPa → kPa