Free CO2 Tank Weight & Runtime Calculator
Determine remaining liquid CO2 by scale weight, convert to gas volume (SCF & Liters), and calculate remaining hours or months of runtime.
🧯 Tank Scale Weight & Application
📊 Remaining CO2 & Estimated Runtime
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Why Pressure Gauges Lie on CO2 Tanks
Unlike compressed air or argon (which are purely gaseous), carbon dioxide inside a cylinder exists in liquid-vapor equilibrium. At standard room temperature (70°F / 21°C), liquid CO2 continuously boils into vapor to maintain a constant saturation pressure of 850 PSI.
The Scale Weight Method is the Only Accurate Metric
The regulator's high-pressure dial will read 850 PSI whether the tank is 100% full or 5% full. The pressure gauge only drops when the very last drop of liquid evaporates, after which the remaining gas depletes in minutes. The only reliable way to know how much CO2 remains is to weigh the tank on a scale and subtract the tare weight stamped on the neck.
Physical Constants
Frequently Asked Questions
Where do I find the Tare Weight (TW) on my tank?
The tare weight is permanently dot-peened or stamped into the metal cylinder neck or collar, usually preceded by "TW" (e.g. "TW 7.7" or "TW 14.2 LB").
Why does the regulator gauge pressure drop in winter?
CO2 vapor pressure is strictly temperature dependent. At 80°F, pressure rises to 970 PSI; at 50°F, pressure drops to 640 PSI. This pressure change reflects room temperature, not gas leakage.
How many draft beer kegs can a 5 lb CO2 tank dispense?
A 5 lb CO2 cylinder dispenses and carbonates approximately 8 to 10 standard full-size half-barrel kegs (15.5 gallons each).