Keg Carbonation Pressure
Regulator pressure to force-carbonate a keg to the volumes you want at the beer’s temperature, corrected for altitude, or the carbonation a setting gives.
The gauge pressure in psi and bar for your target carbonation and beer temperature, or the volumes of CO₂ a regulator setting will give — with the air pressure at your altitude that the gauge reads against.
Example: 2.5 volumes at 38 °F needs 10.8 psi at sea level but 13.4 psi at 5,280 ft; 12 psi at 4 °C at sea level gives 2.56 volumes.
Pressure,
temperature, CO₂.
How Henry’s law links carbonation, temperature and pressure, why the gauge reading changes with altitude, and what the equilibrium figure means.
Henry’s law
At equilibrium the CO₂ dissolved in beer is proportional to the CO₂ pressure above it, and cold beer holds more. The page uses the NIST Chemistry WebBook’s Henry’s-law data for CO₂ in water — 0.034 mol/(kg·bar) at 25 °C, rising as it cools with a factor of 2400 K — to find the absolute pressure for the carbonation you want.
The gauge and altitude
A regulator gauge shows pressure above the surrounding air. Air pressure falls with height, so the same absolute pressure needs a higher gauge setting in the mountains: about 2.6 psi more at 5,280 ft than at sea level. Air pressure comes from the ICAO standard atmosphere.
Equilibrium takes time
Set-and-forget carbonation reaches this figure after several days on gas at a steady temperature. Beer holds slightly less CO₂ than water, and published carbonation charts built from beer may differ a little from this water-based figure.
Stay within ratings
Never set a regulator above the pressure your keg, lines and fittings are rated for, and keep the relief valve working. Inputs stay in your browser; the same anonymous usage counts as the rest of the site apply.
SOURCES
- NIST Chemistry WebBook — Henry’s law data for carbon dioxide
- ICAO Doc 7488, Manual of the ICAO Standard Atmosphere (constants and layer laws)
Last reviewed 24 September 2026. How results are checked: How we verify.