About the Cocktail ABV & Dilution Calculator
Adding up the alcohol in a recipe tells you what goes into the shaker, not what ends up in the glass. Ice adds a lot of water: a shaken sour gains about half its volume in melt, so a mix that starts near 25% ABV is served at around 16%. This calculator predicts that dilution and gives you the finished drink: volume, ABV, sugar and acid, and US standard drinks per serving.
Dilution comes from the equations Dave Arnold fitted to measured drinks in Liquid Intelligence: one for stirred drinks and one for shaken, each a function of the mix’s starting ABV. Built drinks use the stirred curve, blended drinks count every gram of ice you add, and soda or sparkling wine is poured in after the ice, as you would top a highball. Each of the 78 ingredients has its ABV, sugar and acid cited: USDA FoodData Central, retailer lab data, a published juice-acid study and US labelling rules.
A limit worth stating plainly: dilution is an estimate. Your ice, tins and technique will move it by a few points either way. The ABV arithmetic is exact for the amounts and label strengths you enter, and every ABV field can be changed to match your bottle.
Save the drink on screen under a name (kept in this browser), reload any saved drink, and print a menu card listing each drink’s ingredients, finished ABV and standard drinks.
How to Use the Cocktail ABV & Dilution Calculator
Load a classic from the row of IBA recipes, or start with a blank glass and add ingredients. Each line takes an amount in ounces, millilitres, teaspoons, bar spoons (5 ml) or dashes (1/8 teaspoon). The ABV box is pre-filled from the ingredient table, so check it against your bottle: gin runs from 37.5% to 57%, and a US bottling can differ from the European one listed. Pick the method and the result updates as you type. Carbonated toppers such as soda, tonic, ginger beer and sparkling wine are added after the ice.
Why the Recipe’s ABV Is Not the Drink’s ABV
Take the IBA Margarita: 50 ml of 40% tequila, 20 ml of 40% Cointreau and 15 ml of lime juice. That is 28 ml of alcohol in 85 ml of liquid, 32.9% ABV in the shaker. Shaking melts about 52 ml of ice into it, and the drink that reaches the glass is roughly 137 ml at about 20.5%. Nobody leaves the ice out, and the melt is not a flaw: it takes the drink from harsh to balanced. It also means that any strength figure calculated without dilution overstates the drink by a third or more.
Dave Arnold’s Dilution Equations
Arnold measured drink weight before and after chilling across many cocktails and fitted a curve for each method, with dilution given as a fraction of the starting volume and ABV as a fraction:
- Stirred: dilution = −1.21 × ABV² + 1.246 × ABV + 0.145
- Shaken: dilution = −1.567 × ABV² + 1.742 × ABV + 0.203
The shaken curve is printed in the first edition (p. 123) with a plus sign on the squared term. That version predicts that a shaken 40% mix picks up more than its own volume in water, and it misses the book’s own 50–60% target for shaken drinks. The minus-sign form matches both the target and the measurements Arnold published on his Cooking Issues blog (a shaken whiskey sour at 63%, a stirred Manhattan at 50%), so that is the form used here. The one other assumption: volumes add. Ethanol and water shrink by a few percent when mixed, which makes the true ABV slightly higher than calculated. Arnold ignores this too.
Standard Drinks, Not “One Cocktail”
Drinking guidelines count standard drinks, and in the US one is 14 g of ethanol (NIAAA). A 1.5 oz shot of 40% spirit is exactly one. A Manhattan with 2 oz of whiskey and 1 oz of vermouth is 1.6 to 1.8, depending on the whiskey’s proof. A Negroni of 1 oz each of gin, Campari and sweet vermouth is about 1.4. Dilution does not change this number: ice adds water, not alcohol, so a heavily diluted drink still contains all of it. For what those grams do to your blood alcohol over an evening, see the BAC Calculator.
Sugar and Acid: What Balance Looks Like
Sours balance sweetness against acidity. Fresh lemon juice carries about 48 g of citric acid per litre and lime about 46 g (Penniston et al., 2008). A 1:1 simple syrup is about 61 g of sugar per 100 ml. The subscriber balance check compares your drink’s sugar, acid and finished strength with the IBA classics made the same way, so you can see straight away whether a new sour is sharper or sweeter than a Margarita or a Whiskey Sour. Stirred drinks get their sugar from vermouth and liqueurs, which is why the table uses measured sugar for each named bottle rather than a single figure for “vermouth”.
Scaling a recipe up for a crowd? The Recipe Scaler handles the arithmetic for food, and the Cooking Unit Converter moves between ounces, millilitres and spoons. Browse every Cooking & Kitchen tool for more.
Dilution figures are estimates from published regression equations and vary with ice, equipment and technique. Please drink responsibly, and never drive after drinking.
Frequently Asked Questions
How much does ice dilute a cocktail?
More than most people guess. Dave Arnold measured it for Liquid Intelligence and fitted equations to the results: a stirred drink that starts at 30% ABV picks up about 41% of its volume in melted water, and a shaken drink at 25% picks up about 54%. The stronger the starting mix, the more ice melts, because an alcoholic mix can chill below 0°C and every degree of chilling comes from melting ice.
How strong is a Martini or a Margarita, really?
With the IBA specs and Arnold's dilution equations, a Dry Martini (60 ml gin at 40%, 10 ml dry vermouth) finishes around 25.5% ABV in about 101 ml (1.5 US standard drinks), and a Margarita (50 ml tequila, 20 ml Cointreau, 15 ml lime) around 20.5% in about 137 ml (1.6 standard drinks). Stronger gin, a heavier pour or less vermouth moves those numbers; the calculator shows by how much.
What is a US standard drink?
The NIAAA defines one US standard drink as 14 grams of pure alcohol, about 0.6 fluid ounces. That is 12 oz of 5% beer, 5 oz of 12% wine or 1.5 oz of 40% spirit. Many cocktails contain two or more, because they carry more than one shot of spirit plus the alcohol in liqueurs and vermouth.
Why is shaking more diluting than stirring?
Shaking is violent enough to bring the drink close to its coldest possible temperature in about 12–15 seconds, and colder means more ice melted. Stirring is slower and never reaches that point in normal bar practice, so stirred drinks finish warmer and less diluted. Arnold's equations capture this: at the same starting strength the shaken equation always predicts more water.
How accurate is this?
The dilution figure is an estimate: Arnold's equations describe typical bar technique with standard ice, and your ice, shaker and timing will move it by several percentage points. The ABV arithmetic itself is exact for the amounts and label strengths you enter. Sugar and acid come from USDA FoodData Central, retailer lab data and a published juice study, cited per ingredient; brands and batches vary, so edit the ABV to match your bottle.
