Cocktail Recipe Scaler — Batch & Party Calculator

Scaling a cocktail recipe for 40 guests is not simply multiplying by 40. Dilution changes. Ice ratios shift. The citrus that tasted bright in a single shaker starts reading flat in a five-liter batch sitting in a punch bowl. Getting the math right before the party is what separates a genuinely good batch cocktail from a jug of something vaguely rum-adjacent.

This page works through the actual arithmetic — servings per bottle, total volume per batch, alcohol contribution per ingredient, and how to back-calculate from a guest count to a shopping list.

The Foundation: What Counts as One Serving?

Before scaling anything, the unit of measurement has to be fixed. The National Institute on Alcohol Abuse and Alcoholism defines a standard drink as containing 0.6 fluid ounces of pure ethanol — which, for 40% ABV (80-proof) spirits, works out to 1.5 fluid ounces per serving.

That 1.5 oz figure is the anchor for everything below. A classic Daiquiri calls for 2 oz of rum, which means it delivers slightly more than one standard drink worth of alcohol before accounting for the lime juice and simple syrup. A Mojito built with 1.5 oz of rum lands precisely at one standard drink.

The CDC's dietary guidelines define moderate consumption as up to 1 drink per day for women and 2 for men — not a ceiling for party planning, but a useful reference when estimating how much total alcohol a responsible batch should contain across the expected number of servings.

Single-Recipe Reference: The Classic Daiquiri

Ingredient Single Serving Notes
White rum (40% ABV) 2 oz 1 standard drink + ~33%
Fresh lime juice 0.75 oz
Simple syrup 0.5 oz
Total volume (pre-dilution) 3.25 oz

Shaking adds approximately 0.5–0.75 oz of dilution from ice melt, bringing the final poured volume to roughly 4 oz in the glass. For batch preparation, that dilution has to be added deliberately — typically by calculating 20–25% of the total liquid volume in cold filtered water and incorporating it directly into the batch.

Scaling the Math: Guest Count to Batch Volume

The formula is straightforward:

Total batch volume = (servings per guest × guests) × single serving volume

Assume 2 cocktails per guest over a 3-hour event as a baseline estimate (adjust upward for longer events or a drinks-forward crowd).

Example: Daiquiri Batch for 20 Guests

Ingredient Breakdown for 40 Servings

Ingredient Per Serving × 40 Servings Approximate Bottles/Units
White rum 2 oz 80 oz ~2.4 × 750 ml bottles
Lime juice 0.75 oz 30 oz ~20–22 medium limes
Simple syrup 0.5 oz 20 oz ~590 ml (about 2.5 cups)
Dilution water 0.81 oz 32.5 oz —

A standard 750 ml bottle of rum holds approximately 25.4 fluid ounces, so 80 oz of rum requires 3 full bottles with a small overage — round up, not down.

Scaling for Other White Rum Cocktails

Mojito (Per Serving → Batch of 30)

Ingredient Per Serving × 30 Servings
White rum (40% ABV) 1.5 oz 45 oz (~1.8 × 750 ml)
Lime juice 1 oz 30 oz
Simple syrup 0.75 oz 22.5 oz
Soda water 2 oz Add fresh per glass — does not batch
Mint 8–10 leaves Muddle fresh per glass or steep in syrup

Carbonated components like soda water don't hold in a batch. A practical workaround is to batch everything except the soda, store the concentrate, and top each glass individually at service. This preserves carbonation without sacrificing the time savings of batch prep.

ABV of the Final Batch

Knowing the approximate alcohol content of a batched cocktail matters for responsible portioning. The TTB's rum standards confirm that rum must be distilled from sugarcane products at under 190 proof and bottled at no less than 80 proof (40% ABV) — so the starting ABV of the rum in any batch is well-defined.

For a Daiquiri batch where rum is 2 oz of a 3.25 oz pre-dilution serving (61.5% of total volume):

That's roughly wine-strength. Worth knowing when someone pours themselves a generous 6 oz glass instead of 4.

Federal regulations under 27 CFR § 31.233 address advance mixing of cocktails, including requirements relevant to licensed establishments pre-batching for sale. Home batchers are not subject to TTB licensing, but the structural logic — label your alcohol content, track your volumes — translates directly to responsible home hosting.

Quick Reference: Batch Scaling Multipliers

Guests Cocktails Each Total Servings Daiquiri Rum Needed Bottles (750 ml)
10 2 20 40 oz 2
20 2 40 80 oz 4 (rounding up)
30 2 60 120 oz 5
50 2 100 200 oz 8

The NIAAA standard drink definition — 1.5 oz of 80-proof spirits per drink — provides the per-bottle yield baseline: a 750 ml bottle yields approximately 16.9 standard drinks at 1.5 oz each, or roughly 12–13 Daiquiri pours at 2 oz of rum each.

References

The law belongs to the people. Georgia v. Public.Resource.Org, 590 U.S. (2020)