United KingdomTier 3
Sober-up calculator
An estimated BAC in. Roughly how many hours until it reaches 0 mg/100mL out.
Free·No sign-up·Last checked 2026-08-27
Estimate only
Estimate only. Many factors affect BAC. Do not use to decide whether to drive. Not legal or medical advice.
Formula
Hours to 0 mg/100mL = estimated BAC ÷ 15Worked example. 90 mg/100mL ÷ 15 = 6 hours.
Method
Fixed-rate elimination — the same 15 mg/100mL/hour used by the BAC calculator
Elimination runs at a roughly constant rate no matter how the alcohol got there, so this is the same number the BAC calculator subtracts per hour of elapsed time, run in reverse from your current estimate.
Questions
No. The liver clears alcohol at a fixed rate regardless of how alert you feel. Coffee and cold water can make someone feel more awake while their BAC is unchanged, which is part of what makes them risky.
It's a commonly cited average elimination rate for BAC (the metric equivalent of the 0.015%/hour figure used in some other countries). Individual rates vary, roughly 10–20 mg/100mL per hour depending on the person.
Use the BAC calculator with your weight, sex, units and time elapsed to get an estimate, then bring that number here.