🔵 Pressure Conversion

Convert between pressure units for engineering, meteorology, diving, and science. Supports pascals (Pa), kilopascals (kPa), megapascals (MPa), bar, PSI (pounds per square inch), atmospheres (atm), torr, millimeters of mercury (mmHg), and inches of mercury (inHg).

Pressure conversion calculates applied force per unit surface area. The SI base unit is the Pascal (Pa, 1 N/m²). Standard atmospheric pressure (1 atm) is internationally codified by IUPAC as exactly 101,325 Pa (101.325 kPa), equivalent to 1.01325 bar or approx. 14.6959 psi (lbf/in²).

Metrological Standards & Base Equation

1 bar = 14.5038 PSI = 100,000 Pa. 1 atm = 14.696 PSI = 101,325 Pa. 1 mmHg = 133.322 Pa.

Pressure equivalents comply with IUPAC (International Union of Pure and Applied Chemistry) standard conditions and NIST Special Publication 811. Technical and barometric units use exact gravitational acceleration g₀ = 9.80665 m/s².

Primary References: NIST SP 811 (2008 Edition) · BIPM SI Brochure (2019) · Standards Directory

Supported Pressure Units (8 Total)

Pressure Unit Definitions and Scaling Factors
Unit Symbol Unit Name System Equivalent in Pascal
Pa Pascal Metric Reference Standard (1 Pa)
kPa Kilopascal Metric 1 kPa = 1000 Pa
MPa Megapascal Metric 1 MPa = 1000000 Pa
bar Bar Metric 1 bar = 100000 Pa
psi PSI Imperial 1 psi = 6894.76 Pa
atm Atmosphere Other 1 atm = 101325 Pa
torr Torr Other 1 torr = 133.322 Pa
mmHg mmHg Other 1 mmHg = 133.322 Pa

Popular Pressure Conversions

PSI to Bar

psi → bar — tire pressure & automotive

Bar to PSI

bar → psi — industrial pressure gauges

ATM to PSI

atm → psi — scuba diving & depth

Pascals to PSI

Pa → psi — scientific measurements

mmHg to ATM

mmHg → atm — blood pressure & weather

Common Use Cases

  • Tire pressure (PSI↔bar)
  • Scuba diving (atm↔psi)
  • Weather forecasting (hPa↔inHg)
  • HVAC & refrigeration (PSI↔bar)
  • Blood pressure (mmHg)

Frequently Asked Questions

How do I convert PSI to bar?

Divide PSI by 14.5038 to get bar. For example, 36 PSI ÷ 14.5038 = 2.48 bar.

What is standard atmospheric pressure?

Standard atmospheric pressure is 1 atm = 14.696 PSI = 101.325 kPa = 29.92 inHg.