Convert Tyre Pressures

Below are 2 nifty converters (especially useful if you have Overseas manuals).

You can use these to convert Tyre Pressures from PSI to BAR, or from BAR to PSI: Simply replace the red numbers with your values, and we will calculate the answer automatically!

So what is the difference between PSI and BAR (the whole reason to Convert Tyre Pressures)?

The below explanation is courtesy of

Bar is the atmospheric pressure at the sea level, which equals to 100 kilopascals.
Psi is 1 pound of force per square inch.

Convert Tyre Pressures



The pound per square inch or, more accurately, pound-force per square inch (symbol: psi or lbf/in2 or lbf/in2 or lbf/sq in or lbf/sq in)/ pressure per square inch is a unit of pressure or of stress based on avoirdupois units. It has been largely replaced by the pascal. It is the pressure resulting from a force of one pound-force applied to an area of one square inch


The bar is a non-SI unit of pressure, defined by the IUPAC as exactly equal to 100,000 Pa. It is about equal to the atmospheric pressure on Earth at sea level, and since 1982 the IUPAC has recommended that the standard for atmospheric pressure should be harmonized to 100,000 Pa = 1 bar ≈ 750.0616827 Torr. The same definition is used in the compressor and the pneumatic tool industries (ISO 2787).

Atmospheric air pressure is often given in millibars where standard sea level pressure is defined as 1000 mbar, 100 (kPa), or 1 bar. This should be distinguished from the now deprecated unit of pressure, known as the “atmosphere” (atm), which is equal to 1.01325 bar.

Despite millibars not being an SI unit, meteorologists and weather reporters worldwide have long measured air pressure in millibars as the values are convenient. After the advent of SI units, some meteorologists began using hectopascals (symbol hPa) which are numerically equivalent to millibars.

For example, the weather office of Environment Canada uses kilopascals and hectopascals on their weather maps. In contrast, Americans are familiar with the use of the millibar in US reports of hurricanes and other cyclonic storms.

In water, there is an approximate numerical equivalence between the change in pressure in decibars and the change in depth from the sea surface in metres. Specifically, an increase of 1 decibar occurs for every 1.019716 metre increase in depth close to the surface. As a result, decibars are commonly used in oceanography.

Many engineers worldwide use the bar as a unit of pressure because, in much of their work, using pascals would involve using very large numbers.

In the automotive field, turbocharger boost is often described in bars in the metric part of the world (i.e., outside the US).