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Pounds per square inch to bar

Multiply pounds per square inch by 0.0689476 to get bar.

1 psi = 0.0689476 barNIST SP 811
psi
2.0684bar

30 psi = 2.0684 bar

How to convert pounds per square inch to bar

The bar is exactly 100 000 pascals (100 kPa), close to one atmosphere. The pound per square inch is pounds-force per square inch, exactly 6894.757293168 pascals.

Worked example — 30 psi: 30 × 0.0689476 = 2.0684 bar.

Pounds per square inch to bar table

Common conversions. The reverse table is on bar to pounds per square inch.
Pounds per square inchBar
1 psi0.0689476 bar
5 psi0.344738 bar
10 psi0.689476 bar
20 psi1.379 bar
30 psi2.0684 bar
32 psi2.2063 bar
35 psi2.4132 bar
50 psi3.4474 bar
100 psi6.8948 bar

Reverse and related

About pounds per square inch and bar

Pound per square inch (psi)

1 psi = 0.0689476 bar

Definition. Pounds-force per square inch, exactly 6894.757293168 pascals

History and origin

The pound per square inch comes from the imperial system, expressing pressure as pounds-force spread over a square inch. It equals about 6895 pascals.

Current use

Psi is the everyday pressure unit in the United States for tyre pressure, plumbing and compressed air.

Source: NIST SP 811, App. B; ISO 80000-4. Exact SI values are definitional (bar = 10⁵ Pa, atm = 101 325 Pa) or derived from the pound (NIST HB 44) and standard gravity 9.80665 m/s² (psi)

Bar (bar)

1 bar = 14.5038 psi

Definition. Exactly 100 000 pascals (100 kPa), close to one atmosphere

History and origin

The bar was introduced in the early twentieth century by the meteorologist Vilhelm Bjerknes, defined as exactly 100 000 pascals, close to average sea-level air pressure. Its name comes from the Greek for weight.

Current use

The bar is common outside the United States for tyre pressure, diving and weather, where the closely related millibar is also used.

Source: NIST SP 811, App. B; ISO 80000-4. Exact SI values are definitional (bar = 10⁵ Pa, atm = 101 325 Pa) or derived from the pound (NIST HB 44) and standard gravity 9.80665 m/s² (psi)

Where people use this

Pounds per square inch: tyre pressure in the US, plumbing, compressed air. Bar: tyre pressure outside the US, diving, weather. A 32 psi tyre is about 2.2 bar.

How we know this is right
The factor is fixed by the standards that define the units, not chosen — so it is exact, not a measurement:
1 bar = 14.50377377 psi, so 1 psi = 1 ÷ 14.50377377 = 0.0689476 bar.

Every value is carried to full double precision; the display is rounded.

Both units are defined in NIST SP 811, App. B; ISO 80000-4. Exact SI values are definitional (bar = 10⁵ Pa, atm = 101 325 Pa) or derived from the pound (NIST HB 44) and standard gravity 9.80665 m/s² (psi).

Questions people ask

How many bar is 32 psi?

A 32 psi tyre is about 2.2 bar, and 35 psi is about 2.41 bar.

How many bar is 1 psi?

One psi is about 0.069 bar. To convert psi to bar, divide by 14.5.

How do you convert psi to bar?

Divide the psi by 14.5, or multiply by 0.069. A typical 30 psi tyre is about 2.07 bar.

How many bar is 100 psi?

100 psi is about 6.89 bar.

All pound per square inch conversions