Keg calculator
Enter how many guests will drink beer and how long it is served to see how many half, quarter or sixth barrel kegs, or how many cans, to buy. Every figure is rounded up, and you can change any assumption to fit your guests.
What to buy
50 beer drinkers, 4 hours, average drinkers, United States sizes
- Total beers
- 250 beers for 50 beer drinkers over 4 hours, 5 each
- Half-barrel kegs
- 2 kegs 165 pours of 12 oz (355 ml) each
- Or quarter-barrel kegs
- 4 kegs 82 pours of 12 oz (355 ml) each
- Or sixth-barrel kegs
- 5 kegs 55 pours of 12 oz (355 ml) each
- Or cans
- 250 cans 355 ml cans, one per beer
These are planning estimates, rounded up. Each keg size is an alternative: buy only that size, not all of them. Serve alcohol responsibly: offer water and soft drinks, serve food, and help guests get home safely. Read our disclaimer.
Assumptions
The calculator uses these common rules of thumb. Change the inputs above to fit your guests.
| Beers per beer drinker | 2 in the first hour, then 1 per hour |
|---|---|
| Drinking level | light ×0.75, average ×1, heavy ×1.25 |
| One beer | a 12 oz (355 ml) pour from the keg, or one can |
| Pours per keg | half barrel 165, quarter barrel 82, sixth barrel 55 |
| Cans | 355 ml, one per beer |
| Buffer | +10% on every quantity when switched on |
| Rounding | every quantity is rounded up |
How we calculate
- Beers each. Two in the first hour, then one for every hour after that, scaled for light (×0.75) or heavy (×1.25) drinkers.
- Total beers. Beer drinkers × beers each, plus 10% if you switch on the buffer, rounded up.
- Kegs. Total beers ÷ the 12 oz pours in one keg: 165 for a half barrel, 82 for a quarter barrel, 55 for a sixth barrel. Partial kegs don't count, so the result is rounded up. The three sizes are alternatives; you would buy only one of them.
- Cans. One can for every beer, in the can size of the region you choose.
Worked example: 50 beer drinkers, 4 hours
With the default inputs (50 guests who drink beer, average drinkers, a 4-hour party and US can sizes):
- 50 beer drinkers × 5 beers each (2 in the first hour, then 1 an hour for 3 more hours) = 250 beers.
- 250 ÷ 165 pours a half barrel = 1.52, rounded up to 2 half-barrel kegs.
- Or 250 ÷ 82 pours a quarter barrel = 3.05, rounded up to 4 quarter-barrel kegs.
- Or 250 ÷ 55 pours a sixth barrel = 4.55, rounded up to 5 sixth-barrel kegs.
- Or one can for every beer: 250 cans.
The kegs are alternatives. Two half barrels pour 330 beers and five sixth barrels pour 275 beers, so for 250 beers the smaller kegs leave less over.
Questions
How many beers are in a keg?
A half barrel keg pours about 165 beers of 12 oz, a quarter barrel about 82, and a sixth barrel about 55. The calculator uses those pour counts, which leave a little room for foam and the last of the keg.
Which keg size should I choose?
Pick the size whose count is closest to a whole number, because the last keg is the one that may go to waste. A sixth barrel suits a small gathering or a second beer, and a half barrel suits a large party. You can also mix sizes, for example one half barrel and one sixth, to fit your total.
Are kegs the same size outside the US?
The sizes here are US barrel fractions, which are also used in Canada. Kegs sold in other countries often hold different amounts, so check the volume with your supplier and divide it by the number of 12 oz pours. The can size follows the region you pick: 355 ml in the US and Canada, 440 ml in the UK and 375 ml in Australia.
Do I need anything besides the keg?
A keg needs a tap or pump, and it stays colder with plenty of ice in a tub, so plan for the ice as well. The ice calculator covers chilling drinks. Ask your supplier what equipment comes with the keg.
How long does beer stay fresh once the keg is tapped?
That depends on how the keg is tapped. A keg tapped with a hand pump is best finished within a day, and one with a CO₂ tap lasts longer. If your party is a single day, plan to finish the keg that day.
Is it better to buy too much or too little?
Running out is the bigger problem, so the calculator always rounds up. Check whether your supplier takes back an untapped keg, and switch on the 10% buffer if they do.