Convert Standard Atmospheres to Centimeters of Mercury
Convert Standard Atmospheres (atm) to Centimeters of Mercury (cmHg) instantly and accurately.
Conversion Formula
cmHg = atm × 75.99998917
About Standard Atmospheres
The standard atmosphere (atm) = exactly 101,325 Pa - defined by the 10th CGPM (1954) as the reference air pressure at sea level. Used to define STP (0°C and 1 atm) for gas law and thermochemistry. Chemical equilibrium constants (Kp), Henry's law solubility, and thermodynamic tables are tabulated at 1 atm. ISA aviation standard: sea-level 1 atm / 15°C, pressure halving every ~5.5 km. Diving physics: +1 atm per 10 m depth (fresh water) so 30 m = 4 atm absolute. Diamond formation in Earth's mantle: ~50,000 atm. 1 atm = 101,325 Pa.
About Centimeters of Mercury
One centimetre of mercury (cmHg) = 10 mmHg ≈ 1,333.22 Pa. Historical medical and physiological literature used cmHg for intracardiac and intravascular pressures before mmHg became universal. Left ventricular systolic pressure ~12 cmHg; pulmonary artery systolic 2-3 cmHg. Some older European cardiological textbooks and pre-1970s surgical literature report pressures in cmHg. Central venous pressure, cerebral perfusion pressure, and intra-abdominal pressure are occasionally cited in cmHg in legacy datasets. 1 cmHg = 1,333.22 Pa.
Quick Reference Table
| Standard Atmospheres (atm) | Centimeters of Mercury (cmHg) |
|---|---|
| 1 atm | 76 cmHg |
| 2 atm | 152 cmHg |
| 5 atm | 380 cmHg |
| 10 atm | 760 cmHg |
| 25 atm | 1900 cmHg |
| 50 atm | 3800 cmHg |
| 100 atm | 7600 cmHg |