๐บ Pure Alcohol Calculator
Enter the volume and alcohol by volume (ABV%) of your drink to estimate the pure alcohol content in grams, how many "drink units" that represents, and roughly how long it takes your body to process it. Useful for keeping an objective eye on your own drinking or pacing yourself to a moderate amount.
How to use
- Enter the volume you drank (or plan to drink).
- Enter the ABV%, or pick a quick preset like beer or wine.
- See the pure alcohol content, drink units, and estimated hours to metabolize it.
How the calculation works
Pure alcohol in a drink is volume (ml) ร ABV (%) รท 100 ร 0.8. ABV is a percentage by volume, so this first finds the volume of alcohol, then multiplies by alcohol's density (about 0.8 g per ml) to get its weight. A "unit" here is 20 g of pure alcohol, a common reference for drinking in Japan. Twenty grams is roughly a 500 ml bottle of 5% beer or 180 ml (one gล) of 15% sake. Time to metabolise is estimated as pure alcohol รท 6.5, using an average rate of about 6.5 g per hour. The real rate varies widely with body weight, sex, genetics and health, and is much slower in people with low alcohol tolerance.
Worked example
500 ml of 5% beer Pure alcohol: 500 ร 5 รท 100 ร 0.8 = 20 g โ 1 unit Time to metabolise: 20 รท 6.5 โ 3.1 hours 180 ml of 15% sake: 180 ร 15 รท 100 ร 0.8 = 21.6 g, about 1.1 units, and about 3.3 hours to metabolise.
Things to be aware of
- Metabolism times are averages and vary greatly between people. Never use them to decide when it is safe to drive.
- Drink-driving is illegal even after small amounts. If you drink, do not drive.
- Do not drink if you are pregnant, breastfeeding or under the legal drinking age.
- A sensible amount varies by person; if you are concerned about your drinking, seek medical advice.
FAQ
How is pure alcohol content calculated?
We use the formula: volume(ml) x (ABV/100) x 0.8, where 0.8g/ml is the approximate density of ethanol. For example, 500ml of 5% beer contains about 20g of pure alcohol.
What is a "drink unit"?
In Japan, 1 unit is commonly defined as 20g of pure alcohol, a reference amount used in public health guidance.
Is the metabolism time estimate accurate?
This is a rough estimate only, based on an average processing rate of about 6.5g of alcohol per hour. Actual metabolism varies significantly by body weight, sex, liver function, food intake, and other individual factors. This tool is not medical advice, and should not be used to judge fitness to drive.
Can I total up multiple drinks?
Enter the volume and ABV for each drink to check its pure alcohol content, then add them together to get a rough total for the day.
What counts as moderate drinking?
Japan's health ministry guidance flags roughly 40g/day of pure alcohol for men and 20g/day for women as a threshold associated with higher lifestyle-disease risk. Individual factors vary, so use this only as a reference.