A fast, bidirectional pressure converter
Whether you are inflating your car tires, adjusting the pump on an espresso machine, or working with pneumatic tools, you often need to switch between imperial and metric pressure units. This free online pressure converter lets you convert psi to bar and bar to psi instantly.
Because the calculation happens entirely in your browser, the tool is incredibly fast and completely private. No data is sent to a remote server. You can type a value into either the PSI or Bar box, and the opposite field will update immediately as you type.
How to convert psi to bar
The relationship between Pounds per Square Inch (PSI) and bar is fixed by a standard mathematical formula: 1 bar = 14.5037738 psi.
To convert psi to bar manually, you divide the PSI value by 14.5038. For example, if your air compressor gauge reads 32 PSI, dividing by 14.5038 gives you approximately 2.2 bar.
To convert bar to psi, you simply multiply the bar value by the same number. If a water pump is set to 3 bar, multiplying by 14.5038 yields about 43.5 PSI.
Our tool handles this math for you automatically, providing results with up to 8 significant digits to ensure precision for both casual and professional engineering applications.
Common applications for pressure conversion
Tire pressure psi to bar. This is the most common reason people need a pressure converter. Many modern vehicles, especially those manufactured in Europe or Asia, list recommended tire pressures in bar on the driver's door jamb. However, many air pumps at gas stations in the US or UK use PSI. Knowing that 2.2 bar is about 32 PSI, or 2.5 bar is about 36 PSI, ensures you inflate your tires safely and accurately.
Bicycle tires. Road bikes often require high pressure to reduce rolling resistance, sometimes up to 100 or 120 PSI (about 6.9 to 8.3 bar). Mountain bikes, on the other hand, run much lower pressures for better grip, usually around 25 to 35 PSI (1.7 to 2.4 bar).
Espresso machines. High-end coffee machines usually measure pump pressure in bars. The industry standard for a perfect espresso extraction is 9 bar, which translates to roughly 130.5 PSI.
Air compressors and pneumatic tools. Industrial and home workshop compressors often feature dual-scale gauges. If yours only shows one unit, you will need to convert the requirements of your nail gun, impact wrench, or paint sprayer to match your tank's output scale.
Understanding PSI and Bar
PSI (Pounds per Square Inch) is an imperial unit of pressure. It measures the force of one pound-force applied to an area of one square inch. It is the default pressure measurement in the United States and remains widely used in the UK for automotive and plumbing applications.
Bar is a metric unit of pressure, though it is not officially part of the International System of Units (SI). It is defined as exactly 100,000 Pascals (Pa). One bar is very close to the standard atmospheric pressure on Earth at sea level (which is 1.01325 bar). Because it aligns so closely with atmospheric pressure, it is highly intuitive for meteorology, scuba diving, and engineering in metric-using countries.
When using a pressure converter, it is helpful to know the difference between gauge pressure and absolute pressure. Most everyday tools, like tire gauges, measure gauge pressure (often written as PSIG). This means they measure the pressure above the local atmospheric pressure. Absolute pressure (PSIA) includes the atmospheric pressure (roughly 14.7 PSI or 1 bar). This converter assumes you are converting equivalent gauge readings or equivalent absolute readings, as the conversion factor applies identically to both.
Tips for checking and adjusting pressure
- Check tires when cold: Always check vehicle tire pressure when the tires are "cold"—meaning the vehicle has been parked for at least three hours or driven for less than a mile. Friction from driving heats the air inside the tire, causing it to expand and temporarily increasing the pressure reading by 2 to 3 PSI (about 0.15 to 0.2 bar).
- Account for calibration: Keep in mind that analog pressure gauges can lose calibration over time. If your converted numbers are exact but your tires look underinflated or your espresso pulls poorly, your physical gauge might be reading inaccurately.
- Explore other conversions: If you need to convert other measurements for your vehicle, travel, or engineering projects, you might also find our Unit Converter or MPH to km/h Converter useful.