Keg Volume Calculator

A standard half barrel keg holds 15.5 gallons, which equals 1,984 fluid ounces. At 16 fl oz per pint, that's approximately 124 pints — or about 110–115 after accounting for typical foam loss of around 10%.

The best way to estimate remaining beer is to weigh the keg. Subtract the empty keg weight (a standard half barrel weighs about 30 lbs empty), then divide the remaining weight by the density of beer (approximately 8.34 lbs per gallon). Multiply gallons by 128 to convert to fluid ounces.

The most common keg sizes are the half barrel (15.5 gal), quarter barrel or pony keg (7.75 gal), sixth barrel or torpedo (5.16 gal), Cornelius / ball lock (5 gal), and the mini keg (2.64 gal). European 50L and 30L kegs are also widely used.

A rough guideline is to plan for one pint (16 oz) per person per hour. For a 4-hour party with 50 guests, that's 200 pints — requiring just under two half barrel kegs. Use the calculator above to dial in your exact numbers based on keg size and servings per person.

Pouring beer always generates some foam, and there's a small amount of beer that remains at the bottom of a keg that cannot be dispensed. A 10–15% loss is typical for a well-maintained tap system; a poorly adjusted regulator or warm beer line can push that higher.

A half barrel keg (1,984 fl oz) is equivalent to roughly 6.9 cases of 24×12oz cans or bottles. Kegs are generally more cost-effective per ounce, especially when buying in volume, and they generate far less packaging waste.

A Cornelius keg (also called a Corny or ball lock keg) is a 5-gallon stainless steel canister originally used for soda syrup, widely adopted by homebrewers. It holds about 640 fl oz and delivers approximately 40 pint servings — ideal for small gatherings or homebrew setups.

Multiply gallons by 3.78541 to get liters. A half barrel keg (15.5 gal) equals about 58.67 liters; a Cornelius keg (5 gal) equals about 18.93 liters. The calculator shows all volume units automatically once you select your keg size.