Standard Drink Calculator: Count Drinks, Units and BAC

A standard drink is a fixed amount of pure alcohol used for public-health guidance. It is not the same thing as a serving size. In the United States, one standard drink contains 14 grams of pure alcohol. Australia and Ireland use 10 grams, the UK uses 8 grams per unit, and Canada uses 13.45 grams. That is why one pint, glass, or cocktail can count as more than one standard drink depending on where you are and how strong the pour is.

It depends on the size and ABV of the beer. A regular 12 oz beer at 5% ABV is about 1 U.S. standard drink. A light beer at 4.2% is closer to 0.8 U.S. drinks, while a stronger pint or tall craft can can easily count as 1.5 to 2 drinks or more. The only reliable way to know is to calculate using the actual volume and ABV on the label.

A typical 5 oz, or 148 mL, glass of wine at 12% ABV is about 1 U.S. standard drink. The number rises quickly if the pour is larger or the wine is stronger. A restaurant pour can be 175 mL or 250 mL, and many modern wines sit at 13% to 15% ABV, which pushes one glass above one standard drink.

A 750 mL bottle of wine at 12% ABV contains just over 5 U.S. standard drinks. In Ireland or Australia, the same bottle is a little over 7 standard drinks because those systems define each drink with fewer grams of alcohol. That is why sharing a bottle with dinner often means more alcohol than people assume.

ABV means alcohol by volume and is the percentage of the beverage that is pure alcohol. Proof is another labeling system commonly used for spirits in the U.S. It is simply double the ABV, so 40% ABV equals 80 proof. The calculator lets you switch between the two because beer and wine labels usually show ABV, while spirits drinkers often talk in proof.

UK units are based on 8 grams of pure alcohol, while a U.S. standard drink uses 14 grams. Because the UK unit is smaller, the same drink converts into more units than U.S. standard drinks. The drink itself did not change. Only the reporting system changed.

No. Standard drinks are the right place to start, but BAC still depends on body weight, sex, drinking speed, food intake, medications, and time. Two people can drink the same number of standard drinks and reach different BAC values. That is why this page pairs the standard-drink total with a Widmark-style BAC estimate instead of treating drink count alone as the answer.

In U.S. terms, one standard drink contains 14 grams of pure alcohol, which contributes about 98 calories from alcohol alone because ethanol provides 7 calories per gram. Real drinks can be higher than that because beer includes carbohydrates and cocktails can add juice, tonic, soda, syrups, or cream. That is why the calculator shows estimated session calories alongside pure alcohol grams.