Free keg calculator and keg size chart

Keg size chart

A half barrel holds 15.5 gallons, 1,984 ounces or 58.7 liters, enough for 165 twelve-ounce pours. Every other size is in this table, with the pours before any foam or spills.

How to read it

Pours are the ounces divided by the cup, rounded down to a whole cup, which matches the counts the sellers print. A slim quarter holds the same 7.75 gallons as a quarter barrel in a taller, narrower keg. Weights are what sellers list, so treat them as about; the 50 liter row shows two sellers' figures. Liters are to one decimal.

How the calculator works

Kegs to order is the pours you need divided by the pours one keg gives after waste, rounded up. The pours you need are the beer drinkers times the hours times the beers an hour, plus a spare. Each default is listed here with where it comes from.

• Guests who drink beer, 40%. An assumption. It is the beer share of our wedding alcohol calculator's even bar, so the two pages give the same pours. Gratsi says about 30 to 35 percent of guests drink beer when it is served beside wine, so 40 runs a little high. If beer is the main drink, type 70 or more.
• Beers per drinker per hour, 1. One drink per person per hour is the planning rule Gratsi gives, and the one our alcohol calculator uses. A lively crowd runs nearer 1.5 there.
• Spare on top, 15%. Gratsi's 15 percent buffer. It keeps the last keg from running dry in the last hour.
• Waste and foam, 10%. An assumption. GoTab quotes Brent Reynard of Draft Control: operators who track keg loss run about 5 to 7 percent, those who don't "high teens to 20%". A one-night event has no tracking, so we chose 10 and you can raise it.
• Cup size, 12 oz. The 12 oz beer, the unit the chart and the alcohol calculator count in. 16 oz and custom sizes are in the menu.

How many kegs for 25 to 300 guests

The calculator's own output at the defaults: 40 percent of guests drink beer, one beer an hour for five hours, 15 percent spare, 10 percent waste, 12 oz pours. This is an example, not a recommendation for your party.

A lively crowd at one and a half beers an hour turns the 100-guest row into 3 half-barrel kegs, and 16 oz pints into 3. With no waste allowed the same crowd needs 2, which is why the waste box matters most when a total lands near a whole keg.

How long does a keg last once it is tapped?

A keg tapped with a party pump lasts about 12 to 24 hours, because pumping pushes air into the beer. Kegworks says a keg on CO2 keeps as long as an unopened one: 45 to 60 days for unpasteurized draft beer and 90 to 120 days for pasteurized, counted from the day it was filled at the brewery. WebstaurantStore gives 6 to 8 weeks and 3 to 4 months for the same two kinds.

Kegworks recommends keeping kegs at 38 degrees Fahrenheit and attributes that to the Brewers Association's Draught Beer Quality Manual. We did not read the manual, so check it if the number matters to your system.

Ask the venue before you order a keg

Ask whether outside beer is allowed, who taps and pours it, and where a cold keg can stand. Rules about outside alcohol and licenses vary by venue and by state, so read your contract and check with your licensing authority; many venues serve only their own bar. Put the answer, the keg count and the size on the banquet event order so the bar crew and the kitchen read the same numbers.

Kegs are one line of the bar. The free wedding alcohol calculator works out the wine, spirits, toast and ice for the same guests, and the free open bar cost calculator prices an open, consumption or cash bar from your venue's quote. The free venue capacity calculator checks how many guests the room holds before you settle the count.

Sources

We read each of these on October 16, 2026. The keg figures come from sellers' pages, which agree except where noted. The Knot, which our alcohol calculator also cites, blocked us that day, so its figures are not repeated here.

• WebstaurantStore, How Many Beers Are in a Keg?. Updated April 28, 2025. Read October 16, 2026. Gallons and pours for the half, quarter, sixth, Cornelius and mini kegs; 3 to 4 months for pasteurized draft beer and 6 to 8 weeks for unpasteurized.
• Kegworks, Guide to Beer Keg Sizes and Dimensions. October 25, 2022. Read October 16, 2026. Ounces, liters, pours and full and empty weights for each size.
• Wholesale Beer Parts, Standard Keg Size Reference. Undated. Read October 16, 2026. The 30 liter and 50 liter European kegs, and pours and weights for the rest. Its 50 liter row says 141 twelve-ounce pours; we round down to 140, as Kegworks does.
• Wholesale Beer Parts, Keg Weight/Volume. Undated. Read October 16, 2026. Full and empty weights, including the 30 liter and 50 liter kegs.
• Kegco, How To Choose A Keg. December 17, 2019. Read October 16, 2026. Ounces for each size, as a second check on Kegworks.
• Kegworks, How Long Does A Keg Stay Fresh?. March 19, 2020. Read October 16, 2026. About 12 to 24 hours on a party pump; 45 to 60 and 90 to 120 days from filling; 38 degrees Fahrenheit, which it attributes to the Brewers Association Draught Beer Quality Manual (we did not read the manual).
• Gratsi, Drink Calculator. Undated, copyright 2026. Read October 16, 2026. One drink per person per hour plus a 15 percent buffer; about 30 to 35 percent of guests drink beer when it is served beside wine.
• GoTab, How to Cut Draft Beer Loss by 70 Percent (Patricia Mejia). September 10, 2026. Read October 16, 2026. Brent Reynard of Draft Control: operators who track loss run about 5 to 7 percent, those who don't "high teens to 20%", and he flags any keg above 10 percent.
• Wikipedia, Keg. Last edited July 28, 2026. Read October 16, 2026. A cross-check on the half barrel: 15.5 US gallons, 58.67 liters, about 161.5 pounds full.