Your results will appear here.
Enter your values and press Calculate.
The calculator first works out the pure alcohol you drank: number of drinks times volume per drink times ABV as a decimal times 0.789, the density of ethanol. It then applies the Widmark formula: BAC percent equals (alcohol grams divided by (body weight in grams times the distribution factor r)) times 100, minus 0.015 for each hour since your first drink, where r is 0.68 for men and 0.55 for women. The result is floored at zero and time to sober is the BAC divided by 0.015. This is an estimate for education only, not professional advice: real BAC varies with food, medications, metabolism and liver health, and you should never use it to decide whether you are fit to drive. Never drink and drive.
Blood alcohol content is estimated with the Widmark formula, the standard method that divides the pure alcohol you drank by the amount of body water it can distribute into. First the calculator finds the alcohol grams: total drink volume in ml times ABV as a decimal times 0.789 (the density of ethanol). Then BAC percent equals (alcohol grams divided by (body weight in grams times the Widmark factor r)) times 100, minus 0.015 times the hours since your first drink. The r factor is 0.68 for men and 0.55 for women, reflecting average body water differences. The result is floored at zero and time to sober is BAC divided by 0.015.
Worked example: a 70 kg man has 2 drinks of 250 ml at 5% ABV (500 ml total) over 2 hours. Alcohol grams = 500 × 0.05 × 0.789 = 19.7 g. Raw BAC = (19.7 / (70,000 × 0.68)) × 100 - 0.015 × 2 = 0.0414% - 0.030% = 0.011%. Time to sober = 0.011 / 0.015 = about 0.8 hours.
This is a population-average estimate, not a measurement. Your real BAC can differ substantially because of food, medications, metabolism, liver health and hydration, so never use this tool to decide whether you are fit to drive.
Consider this the Widmark formula explained step by step: alcohol grams from your drinks, divided by your body's water volume (the female r factor is 0.55, the male r factor is 0.68), minus the alcohol your liver has already cleared.
Enter your biological sex and body weight in kilograms. Enter the number of drinks, the volume per drink in milliliters and the average ABV percentage. A 355 ml can of 5% beer, a 150 ml glass of 12% wine and a 44 ml shot of 40% spirits are typical per-drink volumes. Then enter the hours since your first drink.
Click Calculate to see your estimated BAC as a percentage, the grams of pure alcohol, your estimated time until sober, and a plain-language impairment band. Because the same drinks keep raising your level for 30 to 90 minutes after your last drink, treat any result near a limit as over the limit. When in doubt, do not drive.
A standard drink in the US contains about 14 grams of pure alcohol, the benchmark used by the NIAAA and the CDC. Equal-alcohol servings look very different: 12 oz (355 ml) of regular beer at 5% ABV, 5 oz (148 ml) of table wine at 12% ABV, or 1.5 oz (44 ml) of distilled spirits at 40% ABV.
Many real-world pours exceed one standard drink, which is the most common reason people underestimate their BAC. A pint of strong IPA at 7% can be 1.5 or more standard drinks, a restaurant wine pour often exceeds 5 oz, and a mixed cocktail may hide two or three shots. Use the volume and ABV fields above to reflect what you actually drank, not what the glass was called.
Impairment begins well before the legal limit. Around 0.02% brings mild relaxation and some loss of judgment. At 0.05%, coordination drops, alertness lowers and response to emergencies slows. At 0.08%, the legal driving limit in most US states, there is clear loss of muscle control and reasoning. At 0.15% and above there is major impairment of balance, vision and self-control. Above 0.30% the risk turns life-threatening, with possible coma and death from respiratory arrest.
Legal limits vary: most US states use 0.08% for drivers 21 and over, Utah uses 0.05%, commercial drivers are typically held to 0.04%, and drivers under 21 face zero-tolerance laws of 0.00% to 0.02%. Many European countries use 0.05% or even 0.00%. You can be charged with impaired driving below the limit if an officer observes impairment, and no calculator estimate can prove you are legally clear.
Use this BAC effects chart as a rough impairment map for education, never as a legal defense or a reason to drive.
Your liver metabolizes alcohol at roughly 0.015% BAC per hour, about one standard drink per hour, and this rate is nearly fixed. It cannot be sped up by coffee, cold showers, exercise or fresh air. The calculator estimates your time to sober as your current BAC divided by 0.015.
General time-to-zero reference: starting from 0.04% takes about 2.7 hours, 0.08% about 5.3 hours, 0.10% about 6.7 hours, 0.15% about 10 hours, 0.20% about 13.3 hours and 0.25% about 16.7 hours. These are averages; your rate can sit anywhere from 0.010 to 0.020 per hour. The classic morning-after trap is real: a heavy night can leave you above the legal limit at breakfast, so plan ahead rather than hoping you feel fine.
The Widmark formula uses a distribution ratio r that reflects average body water: 0.68 for men and 0.55 for women. Alcohol dissolves in body water, so with less water the same dose reaches a higher concentration. On average, men carry about 58% body water and women about 49%, which is why the formula generally estimates a higher BAC for a woman than for a man of the same weight after the same drinks.
Body composition matters beyond sex: fatty tissue absorbs alcohol poorly, so a muscular person and a higher-body-fat person at the same weight can get different results from the same drinks. The calculator uses population averages, which is one more reason the number is an estimate, not a measurement.
In short, your gender changes the r factor the formula uses, which is why two people can drink the same amount and get very different estimates.
Food: eating before or while drinking slows alcohol absorption and can lower your peak BAC, especially protein-rich and fatty meals. Drinking on an empty stomach can produce a peak up to three times higher. But food does not prevent intoxication and does not speed up sobering once alcohol is in your bloodstream.
Rate of drinking: drinking quickly overwhelms the liver's fixed processing rate, so BAC climbs faster than when drinks are spaced out. Medications: many prescription and over-the-counter drugs interact dangerously with alcohol and can amplify impairment even at low BAC. Rising BAC: your level can keep climbing for 30 to 90 minutes after your last drink, so a calculator result taken too soon understates where you are heading. Liver health, age, genetics and hydration all shift the real number away from the average the formula assumes.
Coffee makes you feel more alert but does not lower your BAC: you become a wide-awake drunk with the same impaired reaction time. Cold showers, exercise and fresh air have no meaningful effect on blood alcohol levels. Vomiting only removes alcohol still in your stomach; once it is absorbed into the bloodstream, vomiting does nothing. Eating after drinking slows the absorption of new alcohol but cannot remove what is already circulating.
Feeling fine is not a reliable gauge either, because tolerance can mask impairment signs while reaction time and judgment stay degraded. The only thing that lowers BAC is time, roughly one standard drink per hour, and the only reliable way to ensure you are unimpaired is to wait a full conservative amount of time or not drive after drinking at all.
Every number on this page is an educational estimate built on population averages. The Widmark formula cannot see your genetics, your meals, your medications, your liver function or how fast you drank, and published accuracy analyses put individual variation around plus or minus 20% or more. A calculated 0.00% does not guarantee your actual BAC is zero, and impairment from alcohol can persist even as BAC drops.
Never use a BAC calculator to decide whether you are fit to drive, to pass a legal test, or to settle an argument about sobriety. Only a breathalyzer or blood test measures actual BAC, and even those have their own conditions. If you have been drinking, the safe choice is to arrange another way home. This content is general information, not medical or legal advice; if you need help with alcohol use, contact a local helpline or health professional.
BAC is estimated with the Widmark formula: BAC percent equals (alcohol grams divided by (body weight in grams times the Widmark factor)) times 100, minus 0.015 times hours since your first drink. Alcohol grams come from drink volume times ABV times 0.789. The Widmark factor is 0.68 for men and 0.55 for women. This calculator does all of that math from the inputs above.
It is a reasonable scientific estimate, not a measurement. The Widmark method uses population averages for body water and metabolism, and published analyses put individual variation around plus or minus 20%. Your real BAC can be meaningfully higher or lower because of food, medications, liver health, hydration and drinking speed. Never use it to decide whether you are fit to drive; only a breathalyzer or blood test measures actual BAC.
The body metabolizes alcohol at about 0.015% BAC per hour, roughly one standard drink per hour. From 0.08% it takes about 5.3 hours to reach 0.00%; from 0.15% about 10 hours. The calculator above shows your estimated time to sober from your current BAC. Nothing speeds this up: coffee, cold showers, water and exercise do not work, only time does.
In most US states the limit is 0.08% for drivers 21 and over. Utah uses 0.05%, commercial drivers are typically held to 0.04%, and drivers under 21 face zero-tolerance laws of 0.00% to 0.02%. Many European countries use 0.05% or 0.00%. You can still be charged below the limit if an officer observes impairment, and impairment begins well below 0.08%.
Yes. Women generally reach higher BAC levels than men of the same weight after the same drinks, because women typically carry less body water for alcohol to distribute into. The Widmark factor accounts for this: 0.68 for men versus 0.55 for women. Body composition also matters, since fatty tissue absorbs alcohol poorly compared with muscle.
A US standard drink contains about 14 grams of pure alcohol: 12 oz (355 ml) of regular beer at 5% ABV, 5 oz (148 ml) of wine at 12% ABV, or 1.5 oz (44 ml) of spirits at 40% ABV. Real pours often exceed this: a pint of strong IPA can be 1.5 standard drinks and a restaurant wine pour often tops 5 oz. Counting glasses instead of standard drinks is the most common way people underestimate their intake. Two 12 oz regular beers equal two standard drinks, while two 16 oz craft IPAs at 7% can hold close to four standard drinks.
Eating before or while drinking slows alcohol absorption and can lower your peak BAC, especially protein-rich and fatty meals. Drinking on an empty stomach can produce a peak up to three times higher. But food does not prevent intoxication and does nothing to speed up sobering once alcohol is already in your bloodstream.
No. Only time reduces BAC. Coffee may make you feel more alert but does not speed up alcohol metabolism, you become a wide-awake drunk with the same impairment. Cold showers, exercise, fresh air and vomiting (once alcohol is absorbed) have no meaningful effect. Your liver clears about one standard drink per hour regardless of what you do.
No. A calculated 0.00% does not guarantee your actual BAC is zero, because the estimate can be off by 20% or more, and impairment can persist even as BAC drops. The only reliable way to ensure you are unimpaired is to wait a full conservative amount of time or avoid driving after drinking altogether.
Most likely a difference in body weight, sex or drinking pattern. A lighter person gets a higher BAC from the same drinks because there is less body water to dilute the alcohol. Women generally reach higher levels than men at the same weight. Drinking faster, drinking on an empty stomach and taking medications that interact with alcohol all push your number higher than a friend's.
At 0.30% and above there is risk of stupor, loss of consciousness and life-threatening central nervous system depression; above 0.40% coma and death become likely. These are not numbers to aim at or argue about: if someone is unresponsive, vomiting while unconscious or breathing irregularly after drinking, call emergency services immediately.
No, never. A BAC calculator is an educational estimate for understanding how drinks accumulate and how long sobering takes. It cannot measure your actual blood alcohol level, account for your individual physiology, or prove you are legally clear. If you have been drinking, arrange another way home instead of doing math.
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