Methodology

How the calculators work

Every calculation runs in your browser from transparent, documented assumptions — there's no hidden model. Here are the defaults you can check and override.

Alcohol calculator

• Drinking guests
  About 82% of guests are assumed to drink (adjustable).
• Consumption
  Roughly one drink per guest per hour at the “standard” pace, over the bar hours you set.
• Default mix
  A 45% wine, 35% beer, 20% spirits split, which you can change.
• Bottle yields
  5 glasses per wine bottle, 24 per beer case, ~17 drinks per spirit bottle, and one champagne bottle per 8 guests for a toast.

Budget & cost benchmarks

The U.S. cost benchmark uses a published national average and category percentages from a cited source, shown with the figure's year and a last-reviewed date on eachcost page. Because the source percentages are rounded, category amounts may not sum exactly to the total.

Regional budget, drink-cost and cake-cost defaults are editable starter values for localisation, not sourced local averages, unless a page names a source and last-reviewed date.

Cake calculator

• Serving styles
  Cake as dessert uses one serving per guest; coffee service and tasting slices reduce that baseline.
• Buffer
  The buffer adds extra servings for cutting variance, unexpected guests and staff meals.
• Kitchen sheets
  Backup sheet count assumes 48 kitchen servings per sheet; confirm final cut size with the baker or venue.

Sourced before published

Cost and marriage-license pages are only published once they have official source links, reviewed fields and a freshness date — we'd rather show fewer pages than unsourced numbers.

Privacy by default

Tools store planning data on your device only, with no account required. See the privacy notes for detail.

Last reviewed 25 June 2026.