Party Drink Calculator Methodology

How We Calculate

Most drink consumption at parties follows a predictable per-guest, per-hour pattern. The calculator asks for guest mix, party duration, weather, and whether alcohol is being served, then applies those rates category by category.

waterBottles = ceil(totalGuests × 0.5 × duration)
juiceBoxes   = ceil(kids × 2)                       // not duration-based
kidsSodas    = ceil(kids   × 1.0 × duration)
adultSodas   = ceil(adults × 1.5 × duration)
alcoholDrinks = firstTwoHours × 1.0 + laterHours × 0.5   // per adult, pacing

// Hot-weather multiplier applied to water, juice, soda totals
if (hotWeather) {
  total *= 1.3
}

Default Consumption Rates

Hot-weather multiplier (1.3x) is applied to water, juice, and soda totals. Juice boxes are whole-party rather than per-hour because kids tend to drink them early. Adult alcohol pacing (1 → 0.5 after hour 2) reflects observed slowing as conversation takes over from refilling.

Sources

• CDC and NAEYC child hydration guidance for active play conditions (water and juice baseline).
• National Restaurant Association event-planning guides and catering manuals for adult soft-drink and alcohol pacing across 2–5 hour events.
• Distilled Spirits Council and Dietary Guidelines for Americans for adult alcohol pacing benchmarks (1 standard drink/hr ceiling).
• Retail sampling (Costco, Sam's Club, Target, Amazon — Q1 2026) for water, juice, soda, and beer case pricing.
• Party Genius AI internal planning data — observed leftover-drink rates across 2,300+ simulated parties, used to validate the 0.5 water-per-hour default.

Edge Cases

Very short parties (< 2 hours): the calculator still assumes a minimum of 1 juice box and 1 water per kid to avoid underordering. Outdoor summer parties (>80°F): use the hot-weather toggle — water consumption spikes 30%+, and ice melts fast, so plan for replacement bags. Alcohol-only adult parties: swap the soda-per-adult component out in the UI; the model doesn't auto-do that. Non-alcohol families: leave the alcohol toggle off; the model does not add "mocktails" — you'll handle those as sodas or specialty items in the food calculator.

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