Convert pound-force per square inch to bar.

About this conversion

PSI-to-bar: multiply by 0.0689476. The standard conversion for tire pressure, hydraulic systems, scuba tanks, and any pressure-rated equipment crossing US/metric borders.

Formula

bar = psi × 0.0689476

Real-world examples

Reference values

Tips & tricks

• Mental shortcut: 1 bar ≈ 14.5 psi. Tire pressure 32 psi ≈ 2.2 bar.
• Car tire pressure is shown in psi in the US, bar (sometimes kPa) elsewhere. Doorjamb stickers often show both.
• A "1 bar" boosted turbo engine has 14.5 psi above atmospheric pressure — about doubling the air available to the engine.

Origin & history

PSI (pound-force per square inch) came from US engineering; bar was defined in 1909 by Norwegian meteorologist Vilhelm Bjerknes as a unit slightly less than 1 atmosphere. 1 bar = 100 kPa exactly; 1 atm = 1.01325 bar.

What is a pounds per square inch?

One psi equals about 6,894.76 pascals — the pressure of one pound-force applied over one square inch. US tire pressure (typically 30-35 psi for cars), hydraulics, and engineering specifications.

What is a bar?

One bar equals exactly 100,000 pascals — close to but not exactly equal to one standard atmosphere. European industrial pressure, tire pressure in some regions, and meteorology.

Everyday reference points for psi

To put the unit in perspective, here are a few real-world examples. 3000 psi is a SCUBA tank; 1 psi is a soft pillow pressed against your hand; and 14.7 psi is atmospheric pressure at sea level.

How to convert pounds per square inch to bar

To convert a value from pounds per square inch (psi) to bar (bar), apply the conversion factor shown in the formula above. The calculation is the same whether you do it by hand, in a spreadsheet, or with the live converter on this page.

Steps:

1. Take your input value in psi.
2. Apply the formula see formula above.
3. The result is your value in bar.

For repeated calculations, save the formula in a spreadsheet or use the live converter at the top of this page — it handles the math automatically and displays the result as you type.

Frequently asked questions

How do I convert psi to bar?

Apply the formula psi → bar shown above, or just type your value into the converter at the top of this page. The result updates instantly.

Which is bigger, psi or bar?

This depends on the conversion ratio in the formula. If the factor multiplied by your value gives a larger number, then bar is the smaller unit (so it takes more of them to express the same quantity). If the result is smaller, then bar is the larger unit.

When would I use psi versus bar?

Both units measure pressure, so the choice depends on context. Pounds per square inch is typically used for tires, weather, hydraulics, and material strength; bar similarly. Most professional fields standardize on one or the other based on regional conventions or technical tradition.

How precise is this psi to bar conversion?

The conversion factor shown is the internationally defined exact value (or the best-published approximation if the relationship is irrational, like degrees-to-radians). The live converter on this page uses double-precision floating-point math, accurate to about 15 significant digits — far beyond any practical engineering need.

Is the conversion ratio exact, or an approximation?

Most unit conversions between SI metric units, and between SI and US customary units, have been formally defined as exact values since the 1959 international yard-pound agreement and subsequent SI redefinitions. Exceptions are unit pairs that involve irrational numbers (radians, e.g.) or empirical conversions (like food calories, which depend on temperature). When in doubt, consult the formula at the top of this page.

Related conversions

See also