Blood Alcohol Calculator
Estimate your blood alcohol concentration (BAC) based on drinks, weight, gender, and time, with time to reach 0.05 and 0.00.
1 standard drink = 10g alcohol (a middy of beer, small glass of wine, or 30ml spirit)
How It Works
Uses the Widmark formula: BAC = (drinks x 10 / (weight x gender factor)) - (hours x 0.015). Gender factor is 0.68 for males and 0.55 for females. The elimination rate of 0.015 per hour represents average liver processing. Also calculates time to reach 0.05 and 0.00 BAC.
Frequently Asked Questions
What is the legal BAC limit in Australia?
The legal limit for full licence holders in all states is 0.05 BAC. Learner and provisional drivers must have 0.00 BAC. Professional drivers (taxi, bus, truck) have a 0.00 limit. Penalties vary by state but include fines, licence suspension, and potential imprisonment.
What is a standard drink in Australia?
One standard drink contains 10 grams of alcohol. Examples: a 285ml glass (middy/pot) of full-strength beer, a 100ml glass of wine (13%), a 30ml shot of spirits (40%). Check the label — standard drinks are marked on all Australian alcohol products.
How long does it take to process one standard drink?
Your body processes approximately one standard drink per hour. This rate is relatively constant regardless of weight or fitness. Coffee, cold showers, and food do not speed up alcohol processing — only time works.
Is this calculator legally accurate?
No BAC calculator can be 100% accurate. Actual BAC depends on many factors including metabolism, food intake, medications, liver function, and individual variation. This is an estimate only. If in doubt, do not drive. Use a personal breathalyser or wait longer.
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