Pressure Unit Conversion

Enter a value in any unit below to instantly convert between atm, at, N/m², kgf/cm², psi, psf, bar, mbar, Pa, kPa, MPa, mmAq (mmH2O), mmHg (Torr).

Standard atmosphere (atm)

atm

Technical atmosphere (at)

at

kgf/cm²

Newton per square meter (N/m², Pa)

N/m²

Pound-force per square inch (psi)

psi

Pound-force per square foot (psf)

psf

Bar

bar

Millibar (mbar)

mbar

Pascal (Pa)

Pa

Kilopascal (kPa)

kPa

Megapascal (MPa)

MPa

Millimeter of water (mmAq, mmH2O)

mmAq

Millimeter of mercury (mmHg, Torr)

mmHg

Unit Conversion Relations

1 kgf/cm² = 14.2 psi = 0.98 bar
1 bar = 0.1 MPa = 0.98 atm
1 kgf/cm² = 10000 mmAq = 735.6 mmHg
1 bar = 100 kPa = 100000 Pa = 1000 mbar

FAQ

What is the difference between absolute and gauge pressure?
Absolute pressure is measured relative to perfect vacuum (0 pressure). Gauge pressure is measured relative to atmospheric pressure. For example, tire pressure of 30 psi is gauge pressure; absolute pressure would be 30 + 14.7 = 44.7 psi at sea level.
Why are there so many different pressure units?
Different industries developed their own units: psi for mechanical systems, bar for meteorology and hydraulics, mmHg for medical applications, Pa for scientific work, and atm for general reference. Each unit evolved for specific practical needs and measurement methods.
How do I convert between metric and imperial pressure units?
Key conversions: 1 bar = 14.504 psi, 1 kgf/cm² = 14.223 psi, 1 MPa = 145.04 psi. For example, to convert 5 bar to psi: 5 × 14.504 = 72.52 psi. The calculator handles these conversions automatically with high precision.
What are typical pressure values in different applications?
Atmospheric pressure: 1 atm (14.7 psi), tire pressure: 30-35 psi, hydraulic systems: 1000-5000 psi, steam boilers: 100-1000 psi, vacuum systems: 0.001-0.1 atm, deep ocean: 100+ atm. These ranges help understand pressure scales in various fields.
What do mmHg and mmH₂O measurements represent?
mmHg (millimeters of mercury) and mmH₂O (millimeters of water) are based on the height of liquid columns. 1 mmHg = 1 Torr = 133.3 Pa. 1 mmH₂O = 9.807 Pa. These units are common in medical, meteorological, and low-pressure applications.
How accurate are pressure unit conversions?
The conversions use internationally defined standards. For example, 1 atm = exactly 101,325 Pa by definition. The calculator maintains precision suitable for engineering calculations, system design, and scientific applications, typically displaying 3-4 significant figures.