Pressure Converter

Pressure converter: pascals, bar, psi, atm, and mmHg

This converter relates eight pressure units used in weather, automotive, medical, and engineering contexts: pascals, kilopascals, megapascals, bar, atmospheres, psi, torr, and millimeters of mercury. Pressure is force per unit area, so every value here translates exactly into every other. The conversion factors and the field each unit belongs to are set out below.

The pascal is the base unit

Every conversion runs through the pascal (Pa), the SI unit equal to one newton per square meter. A pascal is tiny — atmospheric pressure is over 100,000 of them — so kilopascals (kPa) and bar are the everyday metric working units, while psi dominates in the US.

Key pressure conversion factors

• 1 kPa = 1,000 Pa
• 1 bar = 100,000 Pa = 100 kPa = 14.5038 psi
• 1 atm = 101,325 Pa = 1.01325 bar = 14.696 psi = 760 mmHg
• 1 psi = 6,894.76 Pa = 6.89476 kPa
• 1 torr ≈ 1 mmHg = 133.322 Pa
• 1 MPa = 1,000,000 Pa = 145.038 psi

Tires and automotive pressure

Tire pressures are the most common everyday use. A typical passenger car runs 32–35 psi, which is 2.2–2.4 bar or about 220–240 kPa. Because air pressure rises as tires heat up, set them when cold. Bicycle tires run much higher — road tires often want 80–120 psi (5.5–8.3 bar).

Weather and barometric pressure

Meteorologists report pressure in hectopascals (hPa) or millibars, which are identical: 1 hPa = 100 Pa. Standard sea-level pressure is 1,013.25 hPa. A deep low-pressure storm system might drop below 980 hPa, while high-pressure fair weather sits above 1,020 hPa.

Medical and scientific pressure

Blood pressure and many laboratory measurements use millimeters of mercury (mmHg), a unit rooted in the original mercury barometer. A normal blood pressure of 120/80 mmHg converts to about 16.0/10.7 kPa. Vacuum systems are often specified in torr, which is practically identical to mmHg.

Related converters

• Energy Converter — pressure and energy appear together throughout thermodynamics.
• Temperature Converter — gas pressure and temperature are tightly linked.
• Area Converter — pressure is force per area, so unit of area matters when you compute force.