Coffee for a Crowd Calculator
Brewing for a meeting, wedding, or fundraiser? Enter your headcount, how much each person drinks, and your ratio to get the grounds, water, total servings, and how many urns it takes to make it all.
Plan about 2 cups each for a morning event, 1–1.5 for the afternoon. Round up for long gatherings.
Formula & how it works
Servings are guests × cups per person. Total water is servings × cup size (1 fl oz ≈ 29.57 mL ≈ 29.57 g). Grounds are water ÷ ratio, and urns are the total volume divided by the urn capacity, rounded up.
Worked example
Thirty guests at 2 cups each of 8 oz is 60 servings, or 480 oz — about 3.75 gallons of water. At a 1:16 ratio that needs roughly 890 g of coffee (about 2 lb), and it takes two 55-cup urns to brew and hold it all.
Planning coffee at scale
Estimate consumption honestly
The biggest source of shortfall is underestimating how much people drink. Two cups a head is a safe morning figure, and the number climbs with event length, cold weather, and how central coffee is to the gathering. It is cheaper to have a little left over than to send someone on a mid-event coffee run.
Match urns to timing
A single large urn is simple, but two smaller ones let you brew a fresh batch partway through so late arrivals do not get stewed coffee. Urns also take time to heat and brew, so factor that in and start early enough that the first cup is ready when guests are.
Round grounds to what you can measure
The calculated grounds will rarely be a tidy number. Rounding up to the nearest convenient scoop or pre-portioned pack is fine — a slightly stronger brew is easily softened with hot water at the urn, and most crowds appreciate having that option anyway.