Keg sizes, pour sizes and how many to buy
The ounces in each keg, how pour size changes servings per keg, and a simple way to size an order for a party or bar.
What each keg size holds
The calculator uses four standard presets measured in fluid ounces. A half barrel, the classic full-size keg, holds 1984 oz. A quarter barrel or pony keg holds 992 oz, exactly half of that. A sixth barrel, also called a sixtel, holds 661 oz, and a corny keg, the five-gallon stainless vessel favored by homebrewers, holds 640 oz. The sixth barrel and corny keg are close in size but not identical, which is why the tool lists them separately rather than treating them as one.
How pour size changes the count
Servings per keg is simply the keg volume divided by the pour, keeping whole pours only. A half barrel gives 124 servings at a 16 oz pint but 165 at a 12 oz cup, because smaller glasses stretch the same beer further. Choosing the right pour is therefore the single biggest lever on your count. If your event mixes pint glasses and cans, run the numbers for the size most people will actually use rather than an average, since the tool counts one pour size at a time.
Sizing an order for a party
Start from a headcount and an estimate of drinks per guest, then multiply to get total servings. A group of 60 guests at about 4 drinks each is 240 servings. Type that into Servings needed and the tool rounds up to the kegs to buy, so 240 pints from half barrels that yield 124 each becomes 2 kegs with a little to spare. Because it rounds up, you never under-order, but for a long event or heavy early drinking it is worth adding a buffer keg on top.
Why the real count often runs higher
The math is deliberately conservative. It ignores foam and head space, so a 16 oz pour is treated as a full 16 oz even though a real glass usually delivers 14 to 15 oz of liquid beer. That means a keg frequently serves a handful more glasses than the number shown. Treat servings per keg as a safe floor rather than an exact yield, and you will rarely run short.