Free BAC Calculator
Estimate your blood alcohol content right now, see when you’ll be sober, and check it against the legal limit where you are — USA, Canada, Australia, UK, India or Ireland.
About you Saved in your browser only
Your drinks Standard US sizes
Simplified demo. The free Alcophone app gives a more accurate estimate (body measurements, meals) and does much more — drink log, statistics, achievements, safe-ride button.
Get the appEstimate only — not a breathalyzer. Never drive after drinking, whatever any calculator says. Nothing you enter leaves your browser.
This page estimates. The app remembers, learns and gets you home.
Same calculation engine — plus everything a one-off web form can’t do.
Drink log & alcohol diary
Every drink with its time, day after day. 30 days free, unlimited history with Premium — the full year, not one night.
Statistics & calendar heatmap
Weekly and monthly totals, drink-free days, streaks and trends — see patterns you’d never notice one night at a time.
CSV export
Your data is yours. Export the whole log any time and open it in Excel, Sheets or with your doctor.
140+ achievements
Levels, tiers and streak rewards for drink-free days, hydration and pacing — habits that stick.
Personalised to your body
The app factors in your body measurements (Navy method) and what you ate — your number, not an average.
5,800+ drinks by name
Beers, craft beers, ciders, seltzers and cocktails with their real ABV — no guessing standard sizes.
Also in the app
- Live BAC countdown & “sober by” notifications
- Predicted BAC before you log a drink
- Water logging & hydration score
- One-tap ride home with your country’s rideshare apps
- Legal limits for every US state, Canadian province, Australian territory, the UK, India and Ireland
- Offline, no account, nothing leaves your phone
How this calculator works
The numbers come from the same code that runs inside the Alcophone Android app. Your total body water is estimated from sex, age, weight and height (a body-fat estimate from BMI, age and sex, with lean and fat tissue weighted separately in the volume of distribution; a separate South Asian model for India). Each drink’s pure alcohol (volume × ABV × 0.789) is distributed into that water volume and eliminated at a rate set by your sex and age, the empty-stomach rate (0.010 % per hour for men, about 0.012 % for women, about 0.0105 % for women from age 65).
The legal limit shown is the one that applies to an adult, full-licence driver where you selected — including lower state limits such as Utah’s 0.05 %, Canadian provincial warn ranges and the Canadian under-22 zero-tolerance rule. Learn more in How BAC Works and check BAC limits by US state, Canada, Australia, the UK, India or Ireland.
Frequently asked questions
How accurate is this BAC calculator?
Any calculation from body size and drinks is an estimate — food, medication, genetics and how fast you drank all shift the real value. This page runs a simplified version of the model. The app personalises the estimate to your body — measurements and meals — so it fits you rather than an average. Only a breathalyzer or a blood test measures actual BAC.
How long until I’m sober after 3 beers?
For many adults, three 12 oz 5 % beers put BAC in the 0.05–0.08 % range, and the average body eliminates about 0.015 % per hour (slow eliminators about 0.010) — so 4 to 6 hours or more after the last one; this calculator uses the empty-stomach rate, though some people clear alcohol even more slowly. Enter your own numbers above; the “Sober by” time is personalised to your body and pace.
Does coffee, a cold shower or food sober you up?
No. Only time lowers BAC. Coffee and cold water make you feel more alert, not less impaired. Eating before drinking slows absorption and lowers the peak; after a real meal BAC also falls somewhat faster, but food never makes you safe to drive, and food eaten afterwards cannot undo alcohol already in your blood.
Can I still be over the limit the morning after?
Yes. If your BAC was 0.15 % at 2 am, it can still be around 0.05–0.08 % at 8 am. Set your last drink to “6 hours ago” above to see how a night out carries into the morning.
Why does the standard drink change when I switch country?
Standard serving sizes differ: a US beer is 12 oz, a UK beer is a pint (568 ml), an Australian one 375 ml. The calculator uses the local defaults so the counts match what you’re actually served — and you can always enter a custom volume and ABV.
Is my data stored anywhere?
No. The calculation runs in your browser and the details you enter are not sent anywhere; your profile is remembered on this device only so you don’t have to retype it. The site itself counts visits with Google Analytics, as our privacy policy explains.
What does the app do that this page doesn’t?
It keeps a full drink log with statistics, a calendar heatmap and CSV export, tracks 140+ achievements, factors in meals and body measurements for a more accurate estimate, predicts your BAC before you log a drink, counts down live with notifications, and calls a rideshare in one tap. This page is a single-shot estimate; the app is the habit.
Know your limit. Get home safe.
Alcophone is free on Android — more accurate, remembers every drink, and gets you a safe ride.
