About this tool
The Keg Servings Calculator is a free, in-browser tool that turns keg size and pour size into the numbers you actually need: how many cups a keg pours, how many kegs to buy for your crowd, and what each beer costs. Pick a keg — half barrel, quarter (pony), sixtel, Cornelius (corny), or 5 L mini — choose a pour size, and set a foam/spillage loss factor. It returns servings per keg immediately, and if you add a guest count and hours it computes how many kegs you need. All calculations run locally in your browser and nothing you enter is uploaded.
The method starts from each keg's volume in fluid ounces: a half barrel (15.5 gal) holds 1,984 oz, a quarter (7.75 gal) 992 oz, a sixtel (5.16 gal) 661 oz, a corny (5 gal) 640 oz, and a mini (5 L) about 169 oz. Usable volume = keg oz × (1 − spillage%), with a default 5% loss to foam and the first few pours. Servings = floor(usable ÷ pour size), where the default pour is 12 oz (a can-equivalent); pint (16 oz), 8 oz, and 5 oz taster pours are also offered. For the crowd estimate it uses the same drinks model as party planning — total drinks = guests × (hours + 1) — and kegs needed = ceil(total ÷ servings per keg).
As a worked example, a half barrel at 12 oz pours with 5% loss yields floor(1,984 × 0.95 ÷ 12) = 157 beers. For 60 guests over 4 hours that is 300 drinks, so you'd need 2 kegs. Enter a keg price and it divides by servings to show cost per pour — often well under a dollar a beer, which is why kegs beat cans for big parties. Real yield varies with temperature, tap technique, and how much foam you pour, so keep the spillage factor honest.