Blood Alcohol Content (BAC) Calculator
Calculate your estimated blood alcohol content using the Widmark formula. Enter drinks consumed, weight, gender, and hours drinking to see BAC and time to sober up.
Drinks Consumed
Drink Type Servings Size (ml) ABV %
0.000%
Current BAC
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Time to Sober (0.00%)
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Legal to Drive
BAC Effects Reference
| BAC Level | Typical Effects |
|---|---|
| 0.020–0.039% | Mild relaxation, slight euphoria, reduced inhibition |
| 0.040–0.059% | Lowered alertness, impaired judgment, mild incoordination |
| 0.060–0.099% | Significant impairment of balance, reflexes, and judgment — driving is dangerous |
| 0.100–0.149% | Slurred speech, significant motor impairment, memory problems |
| 0.150–0.199% | Severe impairment, nausea, vomiting possible |
| 0.200%+ | Dangerous — loss of consciousness, memory blackout, risk of alcohol poisoning |
Disclaimer: This calculator provides estimates only. Individual BAC varies based on metabolism, medications, health conditions, and other factors. Never drive if you have consumed alcohol.
Frequently Asked Questions
What is the legal alcohol limit for driving in Nigeria?
Nigeria's Federal Road Safety Corps (FRSC) follows a blood alcohol limit of 0.05% (50mg/100mL) for private drivers and 0.02% for commercial drivers. These limits were established under the National Road Traffic Regulations. Driving above these limits is a serious offence.
How is BAC calculated using the Widmark formula?
BAC = (Alcohol consumed in grams) ÷ (Body weight in grams × Widmark factor r) − (Elimination rate × Hours). The Widmark factor r is approximately 0.68 for men and 0.55 for women. Elimination rate is typically 0.015% per hour.
How long does it take for alcohol to leave your system?
The body eliminates alcohol at a roughly constant rate of 0.015% BAC per hour, regardless of coffee, cold showers, or food. A person with 0.10% BAC needs about 6–7 hours to reach zero. Only time clears alcohol — no other method works.
What counts as one standard drink?
One standard drink in Nigeria typically means: 1 bottle of beer (33cl at 5% ABV), 1 small glass of wine (150ml at 12% ABV), or 1 shot of spirits (35ml at 40% ABV). All contain approximately 10–14 grams of pure alcohol.
Does eating affect BAC?
Yes. Food slows alcohol absorption significantly. Eating a full meal before drinking can reduce peak BAC by 30–50% compared to drinking on an empty stomach. However, food does not affect the elimination rate — alcohol still leaves your system at the same speed.