About this tool
The Champagne Toast Calculator is a free, in-browser tool that works out how many bottles of champagne or sparkling wine to buy. Pick a mode — a single toast, open sparkling as the drink, or mimosas — and it returns bottles needed, pours per bottle, total pours, cases of 12, and flutes to rent. It handles standard 750 mL bottles and 1.5 L magnums. All the arithmetic runs locally in your browser, so nothing you enter is uploaded.
A 750 mL bottle holds 25.4 oz (a magnum is double). In toast mode the pour is a modest 4 oz, giving 6 flutes per bottle, so bottles = ceil(guests ÷ 6) — the rounding already covers spills. In open-sparkling mode the pour is a full 5 oz (5 glasses per bottle) and consumption follows the drinks-per-hour model of 2 in the first hour plus 1 for each additional hour, so total pours = guests × (hours + 1). Mimosa mode assumes champagne fills about half the glass (2.5 oz), doubling how far a bottle stretches to 10 mimosas each, and uses the same hourly model. Flutes to rent = guests + 10% spares.
As a worked example, a wedding toast for 100 guests needs ceil(100 ÷ 6) = 17 bottles of 750 mL champagne — about 2 cases — and 110 flutes. Serving sparkling as the main drink over 3 hours instead means 100 × 4 = 400 pours at 5 oz, or ceil(400 ÷ 5) = 80 bottles. Chill bottles for several hours before serving and open them just before the toast so the fizz holds.