Torr to atm Conversion

Thermodynamics & Pressure Metrology Standards

Standard atmospheric pressure is defined by the International Committee for Weights and Measures (CIPM) and NIST as exactly 101,325 Pa.

Primary Pressure Conversion Constants

• Exact Definition of 1 atm: 1 atm = 760 Torr = 760 mmHg = 101,325 Pa

• Torr to atm Formula: atm = Torr760

• atm to Torr Formula: Torr = atm × 760

• Pascals (SI Base): Pa = atm × 101,325 = Torr × ((101,325) / (760))

• PSI (Pounds per Square Inch): PSI = atm × 14.69595

• Inches of Mercury: inHg = Torr25.4

Vacuum Pressure Regimes (in Torr)

• Rough / Low Vacuum: 25 to 760 Torr

• Medium Vacuum: 10^-3 to 25 Torr

• High Vacuum (HV): 10^-7 to 10^-3 Torr

• Ultra-High Vacuum (UHV): < 10^-7 Torr

How to Use This Calculator

Enter your Pressure Value (e.g. 760) and Conversion Direction — choose from Torr (mmHg) → Standard Atmospheres (atm), Standard Atmospheres (atm) → Torr (mmHg). Results update instantly as you type — adjust any value to compare scenarios.

The Formula

Formula Reference: Torr to atm Conversion

Input variables:

pressureInputValue — Pressure Value

conversionDirection — Conversion Direction

Computed outputs:

convertedAtmospheres — Standard Atmospheres (atm)

convertedTorr — Torr (mmHg)

pressureInPascals — Pascals (Pa — SI Base)

pressureInKilopascals — Kilopascals (kPa)

pressureInPsi — Pounds Per Square Inch (PSI)

Mathematical relationships extracted from calculation logic:

torr = atm * 760

pa = atm * 101325

psi = atm * 14.6959487755134

bar = atm * 1.01325

Standard: NIST Handbook 44 and BIPM SI unit definitions

Worked Example

760 Torr of barometric pressure corresponds to exactly 1.000000 standard atmosphere (101.325 kPa or 14.696 psi).

Understanding Your Result

Unit conversion precision: round to the same number of significant figures as your original measurement. Converting 6 feet to meters gives 1.8288 m — but if your measurement was approximate (±1 inch), expressing more than 2 decimal places is false precision. For international trade and technical specifications, SI units (meters, kilograms, liters) are the standard. US customary units (feet, pounds, gallons) differ from Imperial UK units: 1 US gallon = 3.785 L vs. 1 UK gallon = 4.546 L.