Pressure Converter
PSI, Bar, Pascal, atmosphere & more
Frequently Asked Questions
How do I convert PSI to bar for tire pressure?
1 psi = 0.0689476 bar, so divide psi by 14.504 to get bar (or multiply by 0.06895). Example: a typical car tire inflated to 32 psi = 32 × 0.06895 = 2.21 bar. Going the other way, multiply bar by 14.504. A 2.4 bar tire pressure = 2.4 × 14.504 = 34.8 psi.
What is standard atmospheric pressure in different units?
Standard atmosphere (1 atm) = 101,325 Pa = 101.325 kPa = 1.01325 bar = 14.696 psi = 760 mmHg = 760 Torr = 29.92 inHg. This is the average air pressure at sea level. At high altitudes pressure drops — Denver (5,280 ft) has about 12.2 psi (84 kPa), and on Mt. Everest’s summit it is only about 4.9 psi (33.7 kPa).
What is the difference between gauge pressure and absolute pressure?
Gauge pressure (psig, barg) is measured relative to ambient atmospheric pressure. Absolute pressure (psia, bara) includes atmospheric pressure. A car tire reading 32 psi on a gauge is actually 32 + 14.7 = 46.7 psia in absolute terms. Vacuum gauges read negative gauge pressure. Weather barometers and blood pressure are always reported as absolute values.
What blood pressure readings are considered normal in mmHg?
Normal blood pressure is below 120/80 mmHg (systolic/diastolic). Elevated is 120–129 systolic. High blood pressure (hypertension stage 1) is 130–139 / 80–89 mmHg, and stage 2 is 140+ / 90+ mmHg. Blood pressure is always measured in millimeters of mercury (mmHg), a traditional unit based on how high a column of mercury is lifted by arterial pressure.
How does altitude affect atmospheric pressure?
Atmospheric pressure decreases roughly 1.2 kPa (0.17 psi) per 100 meters of elevation gain at low altitudes. The approximate formula is P = 101.325 × (1 − 0.0000226 × altitude_m)^5.256 kPa. At 5,000 m (16,404 ft), pressure is about 54 kPa — roughly half of sea level. This affects boiling points (water boils at ~95°C at 2,000 m) and aircraft cabin pressurization.