Estimate your blood alcohol content (BAC) based on drinks consumed, body weight, and time elapsed.
⚠️ This is an estimate only. Never drive after drinking. Always err on the side of caution.
Blood Alcohol Content (BAC) is the percentage of alcohol in your bloodstream. This calculator uses the Widmark formula to provide a rough estimate.
This tool is for educational purposes only and should never be used to determine if it's safe to drive. Actual BAC varies based on many factors. Always use a certified breathalyzer or avoid driving after drinking entirely.
BAC calculators use the Widmark formula, which factors in body weight, biological sex (since body water percentage differs between sexes and affects how alcohol distributes in the body), number of standard drinks consumed, and time elapsed since drinking began, since the liver metabolizes alcohol at a roughly steady rate over time (approximately 0.015% BAC per hour for most people). This is why BAC estimates are genuinely just estimates - individual metabolism, food intake, medications, hydration level, and even genetics can shift actual BAC meaningfully from the calculated number.
Because of this individual variability, no BAC calculator should ever be treated as a reliable way to determine whether it's safe to drive - legal BAC limits exist as a regulatory threshold, not a safety guarantee, and impairment can begin well below the legal limit for many people.
Since the liver processes alcohol at a relatively fixed rate that can't be meaningfully sped up (coffee, cold showers, and food don't actually accelerate alcohol metabolism, despite common belief), estimated time to reach zero BAC is based on that steady elimination rate - but again, this varies by individual and should never be used as the deciding factor for whether it's safe to drive.
Blood Alcohol Content (BAC) estimation formulas, like the widely used Widmark formula, account for the amount of alcohol consumed, body weight, biological sex (due to average differences in body water percentage), and time elapsed since drinking began, since the body metabolizes alcohol at a relatively steady rate over time. These formulas produce an estimate, not a medically or legally precise measurement — actual BAC varies based on factors like food consumption, medications, individual metabolism, and hydration level that a general formula can't fully capture.
Legal driving limits vary by country and sometimes by region within a country, typically ranging from 0.05% to 0.08% BAC for standard drivers, with stricter limits often applied to commercial drivers and drivers under a minimum legal drinking age. Because BAC estimation carries inherent uncertainty, relying on an estimate to determine whether it's safe or legal to drive is genuinely risky — the only reliable way to confirm safety and legality is to avoid driving entirely after drinking.
Because individual alcohol metabolism varies meaningfully from person to person and even day to day for the same person, a BAC calculator should be treated strictly as an educational estimate of general trends, never as a reliable indicator of whether someone is safe or legal to drive. The safest and most reliable approach after drinking is to arrange alternative transportation rather than estimating BAC and deciding to drive based on that number.
No. This is only a rough estimate. Never use this tool to decide whether it is safe to drive - always choose a designated driver or alternate transportation after drinking.
It provides a rough estimate based on the Widmark formula - actual BAC can vary due to individual metabolism, food intake, hydration, and other factors, so it should never be relied on to determine whether it's safe to drive.
Yes, food in the stomach slows alcohol absorption, which can lower peak BAC compared to drinking on an empty stomach, though this effect isn't precisely quantifiable by a calculator.
No, the liver metabolizes alcohol at a relatively fixed rate that isn't meaningfully sped up by coffee, cold showers, or food, despite common belief.
