Why we built this
Throwing a party means a dozen "how much do I need?" questions — and getting them wrong means a dry bar, cold leftovers, or a dance floor nobody can move on. PartyReckon does the headcount math for every part of the plan, in the US units you actually shop in, using the same rules of thumb caterers and event planners rely on.
How we calculate
Every tool uses an established hosting or catering formula. The table documents the exact math and key assumptions behind each calculator.
| Calculator | Core formula | Key assumptions |
|---|---|---|
| Drinks for a Party | Total = guests × hours; split → bottles/cases | ~1 drink/guest/hour; 5 glasses/wine btl, 24/case, 16 shots/btl. |
| Wine for a Party | Glasses = guests × share × hours; ÷ 5 = bottles | 750 ml = 5 glasses. |
| Beer & Keg | Beers = guests × share × hours; ÷24 case, ÷165 keg | Half-barrel = 165 × 12 oz. |
| Coffee for a Crowd | Cups = guests × cups/person; grounds ≈ cups ÷ 32 lb | ~1 lb brews ~32 (8 oz) cups. |
| Food for a Party | Per-person oz by dish type × guests | Protein ~6 oz, sides ~4 oz each. |
| Appetizers per Person | Pieces/person by event type × guests | Cocktail ~10–14, pre-meal ~4–6. |
| Cake Servings | Servings = guests; size from serving chart | Party cut vs wedding cut. |
| Ice for a Party | lb = guests × 1–2 (weather/use) | ~1–1.5 lb/guest, more if hot. |
| Dance Floor Size | sq ft = (guests × % dancing) × 4.5 | ~30–40% dance at once. |
| Tent Size | sq ft = guests × sq-ft-per-person (layout) | Seated round ~12, cocktail ~6. |
| Table & Seating | Tables = ⌈guests ÷ seats per table⌉ | 60" round = 8, banquet = 8–10. |
| Venue Capacity | Max guests = area ÷ sq-ft-per-person | Planning only — fire code sets the legal max. |
The calculators run entirely in your browser in plain JavaScript. Nothing you type is sent to a server or stored — your numbers stay on your device.
Sources & how we keep this accurate
Formulas and constants come from standard hosting and catering references: U.S. standard-drink sizes for the bar tools, caterer/USDA per-person food guidance, standard cake serving charts (Wilton), and event-rental square-foot-per-person figures for space and seating. Each calculator carries its own cited source and a review date. We review the figures periodically and welcome corrections via the contact page.
Methodology last reviewed June 2026
What this is not
PartyReckon gives planning estimates to help you shop and set up. It is not professional catering, safety, or fire-code advice. Always round up a little, serve alcohol responsibly, and confirm a venue's legal maximum occupancy with the venue or local fire marshal — not this tool.
Get in touch
Want a calculator we don't have yet, or spot a number that looks off? Tell us on the contact page.