Is 1 bar exactly 1 atmosphere (atm)?

No, but they are very close. This is a common point of confusion. - 1 bar is defined as exactly 100,000 Pascals (kPa). - 1 atm (Standard Atmosphere) is defined as 101,325 Pascals (kPa). Therefore, 1 atmosphere is slightly larger than 1 bar (1 atm = 1.01325 bar).

Why are car tires in PSI and bar?

It depends on the region. PSI (Pounds per Square Inch) is the standard Imperial unit used primarily in the United States. Bar (and Kilopascals, kPa) is the standard metric unit used in Europe, the UK, and most of the rest of the world. 1 bar is very close to 1 atm, making it an easy-to-use metric standard for atmospheric pressure.

PSI to Bar Converter

Q: What is the formula for PSI to bar?

The formula is: bar = PSI × 0.06894757. To convert from bar to PSI, the formula is: PSI = bar × 14.50377.

Q: How many PSI are in 1 bar?

There are 14.50377 PSI in 1 bar.

A complete pressure unit conversion tool. Enter a value in any field to instantly convert between **PSI**, **Bar**, **Kilopascals (kPa)**, and **Atmospheres (atm)**.

Pounds per Square Inch (PSI)

Bar

Kilopascals (kPa)

Atmospheres (atm)

How to Convert PSI to Bar

Converting from Pounds per Square Inch (PSI) to bar is a common task for checking tire pressure or in engineering applications. The conversion is straightforward.

The Conversion Formula

The relationship between PSI and bar is derived from their definitions in Pascals:

1 bar = 100,000 Pascals (Pa)
1 PSI = 6,894.757 Pascals (Pa)

From this, we get the direct conversion factors:

PSI to Bar: bar = PSI × 0.06894757 (or divide by 14.50377)
Bar to PSI: PSI = bar × 14.50377

PSI vs Bar for Tire Pressure

This is the most common reason for this conversion. Different regions and manufacturers use different units:

PSI is standard in the **United States**. A typical car tire pressure is 30-35 PSI.
Bar is the standard metric unit in **Europe and the UK**. A typical car tire pressure is 2.1-2.5 bar.

Common Tire Pressure Conversion Chart

PSI	Bar (approx.)	kPa (approx.)
28 psi	1.93 bar	193 kPa
30 psi	2.07 bar	207 kPa
32 psi	2.21 bar	221 kPa
35 psi	2.41 bar	241 kPa
38 psi	2.62 bar	262 kPa
40 psi	2.76 bar	276 kPa

Frequently Asked Questions (FAQ)

What is the formula for PSI to bar?

The formula is: bar = PSI / 14.50377. For a quick mental estimate, you can divide the PSI value by 14.5.

How many PSI are in 1 bar?

There are **14.50377 PSI** in 1 bar.

Is 1 bar the same as 1 atm?

No. They are very close, but 1 standard atmosphere (atm) is slightly larger than 1 bar. 1 atm = 1.01325 bar. For most everyday uses (like tire pressure), they are sometimes used interchangeably, but in science and engineering, the distinction is critical.