atm to mmHg Converter

🔒 Runs in your browser — nothing is sent to a server

Convert atmospheres to millimeters of mercury using the exact relation 1 atm = 760 mmHg. So 0.5 atm = 380 mmHg, 2 atm = 1,520 mmHg, 5 atm = 3,800 mmHg. Useful in chemistry for translating fractional-atmosphere lab pressures into Torr-precision mmHg readings, and in vacuum technology where the millimeter-of-mercury scale is standard. Browser-local.

Atmosphere (atm)
Millimeter of mercury (mmHg)

Atmosphere (atm) → Millimeter of mercury (mmHg)

Quick reference table

Atmosphere (atm)Millimeter of mercury (mmHg)
0.1 atm76 mmHg
0.5 atm379.9999 mmHg
1 atm759.9999 mmHg
1.5 atm1139.9998 mmHg
2 atm1519.9998 mmHg
5 atm3799.9995 mmHg

Glossary

Atmosphere (atm)

A standard atmosphere is defined as exactly 101,325 Pa (= 1.01325 bar = 760 mmHg = 14.696 psi). It represents average atmospheric pressure at sea level under standard conditions. Used in chemistry (gas-law problems), high-altitude aviation references and pressure-vessel ratings. Not the same as the technical atmosphere (at, ≈ 98,066.5 Pa) — that is a separate, rarely used unit.

Millimeter of mercury (mmHg)

A millimeter of mercury is the pressure exerted by a 1 mm column of mercury at standard gravity, equal to 133.322 Pa. It is the standard unit for blood pressure (120/80 mmHg) and for vacuum-system pressure in laboratory work. The Torr (named after Torricelli) is essentially the same unit — 1 Torr = 1/760 atm differs from 1 mmHg by less than 0.0001 %.

Metric / SI pressure

In the metric system, pressure is reported in pascals (SI base) or its multiples — kilopascal (kPa, 10³ Pa), megapascal (MPa, 10⁶ Pa) — and the related non-SI unit bar (10⁵ Pa). The millibar/hectopascal (mbar = hPa = 100 Pa) is used in meteorology. All metric units relate by exact powers of ten, so conversions between them are simple shifts of decimal point.

Imperial / US pressure

US engineering and automotive primarily report pressure in pounds per square inch (psi). 1 psi ≈ 6,894.76 Pa, defined as one pound-force per square inch. Standard atmospheric pressure is 14.696 psi. The closely related "psi-gauge" (psi-g) measures pressure above atmospheric, while "psi-absolute" (psi-a) measures total pressure including atmospheric.

Related tools

mmHg to atm
Convert mmHg to atm — 760 mmHg = 1 atm exactly
atm to kPa
Convert atm to kPa — 1 atm = 101.325 kPa exactly
atm to Bar
Convert atm to bar — 1 atm = 1.01325 bar exactly
Pressure Converter
Convert pressure — Pa, kPa, MPa, bar, mbar, atm, mmHg, psi