About this tool
The Coffee for a Crowd Calculator is a free, in-browser tool for large-batch coffee service — urns and percolators, not a single pot. Give it your guest count and it scales the pounds of ground coffee, gallons of water, number of urns, and the disposable cups, creamer, and sugar you should stock. It is built for weddings, conferences, church halls, and office events where you brew by the gallon. All calculations happen locally in your browser.
Servings = guests × cups per guest (about 2 for an all-day party, 1.5 at breakfast), and each serving is a 6-oz 'cup' by default or an 8-oz mug. Total water = servings × serving size, converted to gallons (÷ 128 oz). Grounds use the crowd standard of about 1 lb per 50 six-ounce cups for regular strength — pounds = servings ÷ 50, or ÷ 40 for strong and ÷ 60 for weak — and the tool also shows grounds in cups (1 lb ≈ 5 cups) and the golden-cup tablespoon cross-check (about 1 tbsp per 6 oz of water). Urns needed = ceil(servings ÷ urn capacity) for common 30-, 55-, and 100-cup urns. Add-ons follow caterer rules: creamer ≈ 0.5 oz per guest, one sugar packet per guest, and disposable cups at servings + 15% spares.
As a worked example, 50 guests at 2 cups each is 100 servings: at regular strength that is 100 ÷ 50 = 2 lb of grounds, 100 × 6 = 600 oz ≈ 4.7 gallons of water, and ceil(100 ÷ 55) = 2 urns of the 55-cup size. Percolators brew roughly a cup a minute, so start a 55-cup urn about an hour before you need it.