Free online blood alcohol concentration calculator. Estimate your BAC based on weight, gender, drinks, and time. Understand alcohol metabolism for safe driving reference. | No sign-up · Data never leaves your device · Reference only, not legal advice
Zero Dependencies · Works OfflineEnter weight, gender, drink type/quantity, and time since drinking to estimate BAC
Enter weight, gender, drink type/quantity, and time since drinking to estimate BAC
This calculator uses the Widmark formula, a standard forensic BAC estimation method. Actual BAC varies by food intake, individual metabolism, liver function, etc. Results are for reference only and not legal advice for driving.
Most countries set legal driving limits at 0.05% or 0.08% BAC. The US federal limit is 0.08%. Many European countries use 0.05%. Some countries (e.g. China, Japan) have near-zero tolerance. Always check local laws.
The body metabolizes alcohol at about 0.015% BAC per hour on average. BAC of 0.06% takes ~4 hours to reach zero. Water, coffee, or exercise cannot speed up alcohol metabolism — only time works.