Coffee Quantity Calculator for an Event
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/9/2026
The amount of coffee for a group is calculated with number of people × cups per person (about 1.5 on average), then 10 g of ground coffee and 100 mL of water per cup. For 20 people at 1.5 cups each, 30 cups are needed, i.e. 300 g of ground coffee and 3 L of water.
Explanation
Unlike our coffee-to-water ratio calculator, which gives the right proportion for ONE batch of coffee already decided on, this calculator starts from the number of guests to estimate the total amount to prepare for a group, at a business meeting or a reception. The benchmark most commonly cited by caterers and event organizers is about 1 to 2 cups per person, with an average of 1.5 cups that works well for most contexts — adjust upward for breakfast or a morning meeting, where coffee consumption is generally higher, and downward for a short break later in the day. One point worth keeping in mind: even when coffee is offered for free, only 60 to 70% of attendees actually drink it in practice, which is why the 1.5-cup average (per attendee, not per coffee drinker) remains a reliable benchmark rather than an overestimate. For the brewing itself, this calculator uses a benchmark of 10 g of ground coffee per 100 mL of water per cup — a standard "coffee" cup of about 100 mL, not to be confused with the 250 mL metric cup used for recipes elsewhere on this site (see our kitchen measurement conversion calculator). To adjust this ratio to your own taste rather than using this average benchmark, the coffee-to-water ratio calculator lets you precisely dial in the brewed coffee's strength.
Example: 20 people, 1.5 cups per person
Inputs
Number of people: 20. Cups per person: 1.5.
Calculation
Total cups = 20 × 1.5 = 30. Ground coffee = 30 × 10 = 300 g. Water = 30 × 0.1 = 3 L.
Result
30 cups of coffee are needed, i.e. 300 g of ground coffee and 3 liters of water.
Frequently asked questions
Why 1.5 cups per person rather than 1 cup per coffee drinker?
Because even when coffee is free, only 60 to 70% of attendees actually drink it, while those who do sometimes have several cups over a long event. The 1.5-cup average per attendee present (not per coffee drinker) already absorbs this variability, avoiding the need to separately estimate the share of coffee-drinking attendees.
Should more coffee be planned for breakfast than for an afternoon meeting?
Yes, generally: coffee consumption is higher early in the day or at breakfast than during a short afternoon break. Move the "cups per person" slider toward 2 for a morning breakfast, and toward 1 for a shorter or later break in the day.
Does this calculation work for capsule or pod coffee?
The number of cups to plan for stays the same, but the ground coffee and water amounts only apply to a classic filter coffee brew. For individual capsules or pods, simply plan one capsule per estimated cup, without needing to calculate the ground coffee weight or water volume separately.