Enter the drink and your weight
Understanding pure alcohol grams, and drinking sensibly
"A beer" and "a glass of sake" put very different amounts of alcohol into your body. The common yardstick is pure alcohol in grams. Enter what you drank, its strength and your body weight, and this tool shows the pure alcohol content plus an average estimate of how long it takes to clear.
How to use it
Enter the volume (mL), the alcohol by volume (%) and your body weight. For several drinks, enter the combined volume. Pure alcohol is volume(mL) × ABV(%) ÷ 100 × 0.8, where 0.8 is the density of ethanol.
Typical pure alcohol by drink
500 mL of beer at 5% is about 20 g; one go of sake (180 mL at 15%) about 22 g; 200 mL of wine at 12% about 19 g; 100 mL of shochu at 25% about 20 g; a double whisky (60 mL at 43%) about 21 g. Servings that look nothing alike land close to 20 g once converted.
How much is too much
Japan's Ministry of Health, Labour and Welfare guideline on health-conscious drinking (2024) identifies 40 g or more per day for men and 20 g or more for women as the level that raises the risk of lifestyle-related disease, and recommends tracking your intake in pure alcohol grams. Women tend to have less body water and lower metabolising capacity, so the same amount has a stronger effect.
The "time to clear" figure is an average, not a guarantee
Elimination rate varies widely with body weight, genetics (ALDH2 activity), age, condition and liver function — the same drink can differ by hours between people. The estimate here is an average and does not guarantee that alcohol has left your body. After a late night it is common for alcohol to remain in your breath the next morning.
Never drive after drinking, whatever the timer says
Under Japan's Road Traffic Act, 0.15 mg of alcohol per litre of breath already counts as drink-driving. Nothing on this page is a legal basis for deciding you are safe to drive. Alcohol is also dehydrating, so it is worth checking your daily target with the water intake calculator.
Frequently asked questions
How is the metabolism time calculated?+
It is only an average estimate.
Does the time vary from person to person?+
This value is an average estimate only.
Can I use this to decide whether to drive?+
Even small amounts impair driving, and any alcohol remaining is an offence. Do not drive after drinking, regardless of time.
What is a unit of pure alcohol?+
It is used as a health guideline.
Are my inputs stored?+
・Pure alcohol (g) = volume (mL) × ABV (%) ÷ 100 × 0.8 (density of ethanol)
・Time (h) ≈ pure alcohol ÷ (weight kg × 0.1), assuming ~0.1 g/kg eliminated per hour
・Alcohol pharmacokinetics has several models (e.g. Widmark) with a range of coefficients; this is a simple average approximation.
・Ministry of Health, Labour and Welfare, Japan (2024). Guideline on health-conscious drinking: 40 g/day (men), 20 g/day (women) raise lifestyle-disease risk
・Order for Enforcement of the Road Traffic Act, Art. 44-3 (drink-driving threshold: 0.15 mg per litre of breath)
This site does not represent any medical or public body and does not guarantee the accuracy of the results. The metabolism time is a highly individual estimate and does not indicate that no alcohol remains. Never use it to judge fitness to drive. Consult a physician or professional for decisions about drinking and health.