Pressure Converter

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PSI • bar • kPa • atm • mmHg

Pressure Value ⓘ

From

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Enter a pressure to convert

How to Use the Pressure Converter

Enter a pressure — e.g. 32 for 32 PSI (common tire pressure), or 1 for 1 atm (atmospheric pressure).
Select From unit — PSI (US tires/hydraulics), bar (European tires), kPa (weather/SI), atm (science), mmHg (blood pressure).
All five pressure units shown at once — PSI, bar, kPa, atm, and mmHg all displayed simultaneously.
Tire pressure tip — recommended tire pressure is usually 32–35 PSI = 2.2–2.4 bar. Check your car's door jamb sticker for the exact value.

Benefits

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Tire Pressure

Convert PSI to bar for European cars and tire pressure gauges that show bar instead of PSI.

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Blood Pressure

Blood pressure is measured in mmHg worldwide. Understand what those numbers mean in other units.

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Weather & Altitude

Convert barometric pressure readings between kPa, inHg, and atm for weather and aviation.

Pressure Conversion Guide — PSI, Bar, kPa & More

Pressure conversion is needed in three main everyday contexts: tire pressure (PSI in the US, bar in Europe), blood pressure (universally in mmHg), and weather/barometric pressure (inHg in the US, hPa/mbar internationally). The standard atmospheric pressure at sea level is 14.6959 PSI = 1.01325 bar = 101.325 kPa = 1 atm = 760 mmHg = 29.9213 inHg.

Tire pressure: Most passenger cars run at 32–35 PSI = 2.2–2.4 bar. SUVs and trucks: 35–40 PSI = 2.4–2.8 bar. Low tire pressure (under 25 PSI = 1.72 bar) reduces fuel economy, handling, and tire life. Always check tire pressure when cold (driven less than 1 mile). Tires naturally lose 1–2 PSI per month and 1 PSI per 10°F temperature drop.

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Tire Pressure Guide

Passenger car: 32–35 PSI = 2.2–2.4 bar. Truck/SUV: 35–40 PSI = 2.4–2.8 bar. Bicycle road: 80–130 PSI = 5.5–9 bar. Mountain bike: 22–35 PSI = 1.5–2.4 bar. Basketball: 7.5–8.5 PSI = 0.52–0.59 bar.

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Blood Pressure

Normal: 120/80 mmHg. Elevated: 120–129/80 mmHg. High stage 1: 130–139/80–89 mmHg. High stage 2: 140+/90+ mmHg. Crisis: 180+/120+ mmHg. All BP is in mmHg worldwide.

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Weather Barometric

Normal: 29.92 inHg = 1013 hPa = 101.3 kPa. High pressure: above 30.2 inHg = 1023 hPa. Low pressure: below 29.6 inHg = 1002 hPa. Storms: below 980 hPa.

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Altitude & Pressure

Sea level: 101.3 kPa = 14.7 PSI. Denver (5,280 ft): 84 kPa = 12.2 PSI. Mt Everest summit: 33.7 kPa = 4.89 PSI. International Space Station cabin: 101 kPa (same as sea level).

Formula & Logic

Pressure is force per unit area, and the number of units in circulation reflects how many fields measure it independently. The pascal is one newton per square metre and is inconveniently small, so weather uses hectopascals, engineering uses bar or megapascals, and US practice uses psi. The critical distinction is gauge versus absolute: a tyre pressure of 32 psi means 32 psi *above* atmospheric, so the absolute pressure inside is about 46.7 psi. Mixing the two produces errors of a full atmosphere, which is catastrophic in vacuum or altitude work and merely wrong at the kerb.

pascals = value × factor_fromresult = Pa ÷ factor_to1 psi = 6,894.757 Pa · 1 bar = 100,000 Pa · 1 atm = 101,325 Pa

where:

pascal: N/m², the SI unit
bar: 100 kPa — close to but not equal to one atmosphere
atm: standard atmosphere, exactly 101,325 Pa = 14.6959 psi
psig: gauge pressure; psia is absolute — psia = psig + 14.696

Assumptions: Converts the numeric magnitude only. Whether a figure is gauge or absolute is a property of the measurement, not the unit, and must be tracked separately.

SourceNIST SP 330: non-SI units accepted for use with the SI

Step-by-Step Example: 32 psi of Tyre Pressure

A US tyre placard figure converted for a European gauge, and then to absolute pressure.

Tyre pressure32 psi (gauge)

To pascals: 32 × 6,894.757 = 220,632 Pa.
To kilopascals: 220,632 ÷ 1,000 = 220.63 kPa.
To bar: 220,632 ÷ 100,000 = 2.206 bar.
Now the gauge-to-absolute step: 32 psi gauge + 14.696 = 46.70 psia.
Confirm in metric: 220,632 + 101,325 = 321,957 Pa absolute, or 3.22 bar.

Result32 psi = 220.63 kPa = 2.21 bar (gauge)

European placards usually quote about 2.2 bar for the same tyre, confirming the conversion. Pressure also rises roughly 1 psi per 10 °F of temperature, which is why tyres read low on a cold morning and why the placard specifies a cold reading.

Pressure Conversion FAQ

How do you convert PSI to bar? ▾

1 PSI = 0.0689476 bar. To convert PSI to bar: multiply by 0.0689476. Quick mental math: divide PSI by 14.5 for a close estimate. Common tire pressure conversions: 30 PSI = 2.07 bar. 32 PSI = 2.21 bar. 35 PSI = 2.41 bar. 40 PSI = 2.76 bar. 50 PSI = 3.45 bar. Reverse: 1 bar = 14.5038 PSI.

What is normal tire pressure in bar vs PSI? ▾

Most passenger cars: 32–35 PSI = 2.2–2.4 bar. SUVs/trucks: 35–40 PSI = 2.4–2.8 bar. Your exact recommended pressure is on a sticker inside the driver's door jamb or in the owner's manual — not on the tire sidewall (that shows maximum pressure, not recommended). Always check when cold. Underinflated tires reduce MPG by 0.2% per PSI under recommended pressure and increase blowout risk.

How many PSI is 1 atmosphere? ▾

1 standard atmosphere (atm) = 14.6959 PSI = 1.01325 bar = 101,325 Pa = 101.325 kPa = 760 mmHg = 29.9213 inHg. Standard atmospheric pressure is the average air pressure at sea level. It decreases with altitude: at 5,000 ft = 12.23 PSI. At 10,000 ft = 10.1 PSI. At 30,000 ft (aircraft cruising altitude) = 4.36 PSI (cabin is pressurized to about 10.9 PSI = 75 kPa).

What is blood pressure in mmHg and why that unit? ▾

Blood pressure is always measured in millimeters of mercury (mmHg) because the original sphygmomanometers (blood pressure cuffs) literally used a column of mercury to measure pressure. A normal blood pressure of 120/80 mmHg means the systolic pressure (heart pumping) is 120 mmHg and diastolic (resting) is 80 mmHg. In SI units: 120 mmHg = 16,000 Pa = 16 kPa = 2.32 PSI — far too low-sounding for clinical use, which is why mmHg stuck.

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