Sober-Up Time Calculator
The body clears alcohol at roughly 0.015% BAC per hour. Enter your estimated current BAC to see how long it takes to reach zero.
This is a rough estimate only and must not be used to decide whether you are fit to drive or make any medical or legal decision. Metabolism varies widely between people; when in doubt, do not drive.
The Sober-Up Time Calculator estimates how long it takes for an existing blood alcohol concentration (BAC) to clear from your system. Rather than working out your BAC from drinks consumed, it starts from a BAC figure you already have and counts down at the average elimination rate of about 0.015 percentage points per hour. It also flags when you would drop below the common 0.08 percent legal driving limit.
Formula
hoursToSober = BAC ÷ 0.015
- BAC
- Current blood alcohol concentration in percent
- 0.015
- Average alcohol elimination rate in percent per hour
How it works
- Enter your current estimated blood alcohol concentration as a percentage (for example 0.12 for 0.12%).
- The calculator divides that figure by 0.015, the typical amount of BAC the liver clears per hour, to find the hours until you reach zero.
- If your BAC is above 0.08, it also computes how long until you fall below that legal threshold by clearing only the excess.
Worked example
A person estimates their current BAC at 0.12%.
- Hours to sober = 0.12 ÷ 0.015 = 8 hours.
- Excess above the 0.08 limit = 0.12 − 0.08 = 0.04.
- Hours to legal = 0.04 ÷ 0.015 = about 2.67 hours (2h 40m).
About 8 hours to reach 0.00%, and roughly 2h 40m to drop below 0.08%.
Frequently asked questions
- Can anything speed up sobering up?
- No. Coffee, cold showers, exercise, and water do not change how fast your liver metabolises alcohol. Only time lowers your BAC, and this calculator estimates that time.
- Is the 0.015 per hour rate the same for everyone?
- It is only an average. Actual elimination rates vary with genetics, liver health, sex, food intake, and tolerance, so an individual could clear alcohol noticeably faster or slower than the estimate.
- Can I use this to decide if I am safe to drive?
- No. This tool is for general education only and is not accurate enough to judge fitness to drive or to make any medical or legal decision. If you have been drinking, the safe choice is not to drive.