๐งฎ About BAC Calculation
How accurate are BAC calculators?
BAC calculators provide estimates based on average metabolism rates. Actual BAC can vary 20-30% based on: food in stomach, individual metabolism, medications, fatigue, and tolerance. They're useful for general awareness but should never be used to determine if you're safe to drive. When in doubt, don't drive.
How is blood alcohol content determined?
BAC is calculated using the Widmark formula: the grams of alcohol consumed divided by body weight (adjusted for gender), minus the amount metabolized over time. Blood tests measure BAC directly. Breathalyzers estimate it from breath alcohol. Our calculator uses the same Widmark formula used by law enforcement.
What is the alcohol metabolism rate per hour?
The average person metabolizes alcohol at about 0.015-0.017% BAC per hour. This equals roughly one standard drink per hour. However, this rate varies by individual - some people metabolize faster or slower. Factors include liver health, genetics, age, and regular alcohol consumption patterns.
Why does gender affect BAC?
Women typically have higher BAC than men after the same amount of alcohol because: 1) Women have less body water (alcohol dilutes in water), 2) Women have more body fat (alcohol doesn't dissolve in fat), 3) Women have less of the enzyme that breaks down alcohol in the stomach. This is reflected in the Widmark formula's gender constants.
๐ Driving & Legal Limits
When can I drive after drinking?
As a rough guide, your body eliminates about one standard drink per hour. Use our calculator to estimate when your BAC might reach 0.00%. However, impairment can occur even below legal limits. The only safe option is to wait until completely sober, use a designated driver, or take a taxi/rideshare.
How much can I drink and still drive?
There's no guaranteed safe amount. Legal limits vary (0.08% in US/UK, 0.05% in much of Europe, 0.00% in some countries). However, impairment begins well before reaching legal limits - reaction time and judgment are affected from the first drink. The safest answer: if you're driving, don't drink at all.
How long does alcohol stay in your system?
Alcohol is detectable in: Blood for up to 12 hours, Breath for 12-24 hours, Urine for 12-48 hours (or 72+ with EtG tests), Hair for up to 90 days. For BAC purposes, count on eliminating about 0.015% per hour. After heavy drinking, it may take 12+ hours to reach 0.00% BAC.
How many drinks is 0.08 BAC?
It varies greatly by person! For a 160lb (73kg) man, roughly 4 drinks in 1 hour might reach 0.08%. For a 120lb (54kg) woman, it might only take 2-3 drinks. Factors like food, drinking speed, and individual metabolism all affect this. Use our calculator for a personalized estimate.
What is the blood alcohol limit in different countries?
Common limits: USA/UK: 0.08%, Australia/Germany/France: 0.05%, Japan: 0.03%, Romania/Hungary/Czech Republic: 0.00% (zero tolerance). Commercial drivers often have lower limits (0.04% in US). Some countries have different limits for new drivers. Always check local laws.
๐บ Understanding Alcohol
What is a standard drink?
A standard drink contains about 14 grams (0.6 oz) of pure alcohol. This equals: 12 oz (355ml) of beer at 5% ABV, 5 oz (150ml) of wine at 12% ABV, or 1.5 oz (44ml) of spirits at 40% ABV. Cocktails often contain 2-3 standard drinks. "Strong" beers and wines have more alcohol per serving.
What factors affect how drunk I feel?
Many factors beyond BAC affect impairment: Food (eating slows absorption), Sleep (fatigue amplifies effects), Medications (many interact with alcohol), Tolerance (regular drinkers may feel less impaired at same BAC but are still impaired), Mood and stress, Carbonation (speeds absorption), Drinking speed.
Can coffee or food sober me up faster?
No. Only time reduces BAC. Coffee may make you feel more alert but doesn't speed up alcohol metabolism - you'll be a "wide-awake drunk." Food eaten BEFORE drinking slows absorption, but eating AFTER won't reduce existing BAC. Cold showers, exercise, and fresh air also don't help metabolize alcohol faster.
How much alcohol is too much?
Health guidelines suggest: Men - no more than 2 standard drinks/day, Women - no more than 1 standard drink/day, with some alcohol-free days each week. Binge drinking (4+ drinks for women, 5+ for men in 2 hours) is harmful even occasionally. BAC over 0.30% can be life-threatening.
๐ฑ Using This Calculator
How do I use the BAC calculator?
1) Select your gender, 2) Enter your weight, 3) Add the drinks you've consumed using the + buttons, 4) Enter hours since your first drink, 5) Click Calculate. The result shows estimated BAC, impairment level, and time until sober. Remember: this is an estimate only.
Is my data saved or shared?
No. All calculations happen in your browser. We don't collect, store, or transmit any data you enter. Your weight, drinks, and results never leave your device. This is completely private and anonymous.
What if I had different types of drinks?
Add each type separately using the counters. A cocktail might count as 1-2 shots depending on size. Strong craft beers (7-10% ABV) count as 1.5-2 regular beers. Large wine glasses (8+ oz) count as 1.5+ standard glasses. When unsure, round up to be safe.