Bar, Atmospheres, PSI: How to Convert Tire Pressure and More

Tire pressure, atmospheric pressure in a weather forecast, and equipment specs are often given in different units — PSI, bar, atmospheres, millimeters of mercury. Let's look at how to quickly convert one into another.

What the converter converts

The pressure converter converts values between pascals (Pa), kilopascals (kPa), bar, atmospheres, millimeters of mercury (mmHg), and PSI (pounds per square inch). Enter a number into any field, and the other units update instantly.

Tire pressure

The most common everyday case is inflating tires. American gauges and some European ones display pressure in PSI, while Russia and many other countries use bar or atmospheres. For example, a typical passenger car tire pressure of 2.2 bar is roughly 32 PSI, or about 220 kPa. If a tire or your car's manual specifies a value in PSI but your gauge reads in bar, the converter shows the match instantly.

Atmospheric pressure

In meteorology, atmospheric pressure is traditionally measured in millimeters of mercury (in Russia and some other countries) or hectopascals (in international weather reports). Reference value: 1 atmosphere = 760 mmHg ≈ 101.3 kPa.

Reference values for a quick estimate

• 1 bar ≈ 0.987 atmosphere ≈ 100 kPa
• 1 atmosphere = 760 mmHg ≈ 101.3 kPa
• 1 PSI ≈ 6.895 kPa ≈ 0.0689 bar

How the calculation works

The conversion uses the pascal as the reference unit — this allows accurate conversion between any pair of units, not just the most common ones.

Bottom line

Converting between PSI, bar, atmospheres, and other pressure units comes in handy when inflating tires using a foreign gauge, reading weather reports, and working with technical documentation. The converter recalculates the value instantly, with no formulas or coefficients to memorize.