PSI to Bar
Convert psi to bar instantly. Free, fast, no signup.
How to use this tool
- Enter psi in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your bar and the full breakdown beneath it.
Convert psi to bar instantly. Free, fast, no signup.
Formula
Bar = PSI × 0.0689476
1 psi (pound-force per square inch) = 6,894.757 Pa. 1 bar = 100,000 Pa. Therefore: 1 psi ÷ 100,000 Pa/bar × 6,894.757 Pa/psi ≈ 0.0689476 bar.
How it works
To convert PSI to bar, multiply the pressure in PSI by 0.0689476. PSI measures force in pounds applied over one square inch, while bar is a metric unit defined as 100,000 pascals. The conversion uses the SI definition of the pound-force and the exact length of an inch to derive the factor. This conversion is common in tyre pressure, hydraulics, and industrial process engineering.
Common mistake: Confusing PSI with kPa (kilopascals). Bar and kPa are both metric but differ by a factor of 10 (1 bar = 100 kPa), so applying a bar conversion to get kPa — or vice versa — produces a tenfold error.
Worked example
Convert 1 PSI to bar
- Start with the input: 1 PSI.
- Apply the conversion factor: 1 × 0.0689475729 = 0.0689475729.
- Round to four decimal places: 0.0689 bar.
1 PSI = 0.0689 bar
Common mistakes to avoid
- Using 0.069 instead of 0.0689476, introducing ~0.15% error — consequential in precision pneumatic or hydraulic systems.
- Confusing gauge pressure (PSIg) with absolute pressure (PSIa): gauge readings omit atmospheric pressure (~14.7 psi), so they must be converted consistently.
- Entering kPa values in the PSI field — 1 kPa is approximately 0.145 psi, not 1 psi, giving results ~7x too large.
Key terms
- PSI (Pounds per Square Inch)
- A unit of pressure in the US customary system, measuring the force in pounds-force applied over one square inch of area. Commonly used for tyre and hydraulic pressures in the US.
- Bar
- A metric unit of pressure defined as exactly 100,000 pascals (Pa). Widely used in meteorology, hydraulics, and European tyre pressure ratings.
- Pascal (Pa)
- The SI unit of pressure, equal to one newton per square metre. It is the base unit from which bar and other pressure units are derived.
- Gauge vs. Absolute Pressure
- Absolute pressure is measured relative to a perfect vacuum; gauge pressure is relative to atmospheric pressure (~14.7 psi / ~1.013 bar). Always clarify which type is intended when converting pressure values.
Frequently asked questions
- How do I convert psi to bar?
- Multiply the number of psi by 0.0689476 to get bar.