A "standard drink" is a fixed amount of pure alcohol that lets you compare a can of beer, a glass of wine, and a shot of spirits on the same scale — but the size of that fixed amount is not the same in every country. This calculator converts any beverage's volume and ABV into pure alcohol grams, then into standard drinks for the US, UK, or Australian definition.

How the calculator works

The calculation happens in two steps. First, the beverage's volume (converted to milliliters if entered in fluid ounces) is multiplied by its ABV percentage and by 0.789 g/ml — the density of pure ethanol — to get the grams of pure alcohol in the drink. Second, that gram figure is divided by the grams-per-drink used in the selected country's guidelines: 14 g in the United States (NIAAA), 8 g in the United Kingdom (NHS unit), or 10 g in Australia (NHMRC). Because the numerator (pure alcohol grams) never changes with the country selected, only the divisor does, a beverage with a smaller standard-drink size like the UK's 8 g will always report a higher "drink count" than the same beverage measured against the US's 14 g.

Inputs and what they mean

Volume is the beverage's serving size, entered in fluid ounces or milliliters — common values are 12 oz for a beer can, 5 oz for a standard wine pour, and 1.5 oz for a spirit shot. ABV (alcohol by volume) is the percentage printed on the label; it varies more than most people expect, from about 4% for a light session beer up to 12-14% for wine and 35-45%+ for spirits and fortified wines. The country selector doesn't change the pure-alcohol math — it only changes which grams-per-drink figure the result is divided by, matching the guideline you actually want to compare against.

Limits and edge cases

This calculator reports a beverage's alcohol content in standardized units; it does not estimate blood alcohol concentration, impairment, or how a specific person's body will process that alcohol — those depend on body weight, sex, food intake, and metabolism, which are outside its scope. It also does not represent official drinking-guideline thresholds (e.g. the NHS's 14-units-per-week guidance) as a pass/fail judgment — it simply converts your beverage so you can compare it against whatever guideline applies to you. Craft and premium beverages increasingly carry higher ABV than their traditional counterparts, so always use the labeled ABV rather than assuming a category average.