BAC Calculator – Calculate Intoxication Level

  • Adam
  • November 1, 2025

Free BAC calculator to estimate your blood alcohol concentration based on drinks consumed, body weight, gender, and time drinking. Understand intoxication levels and legal driving limits.

๐Ÿท ๐Ÿ“Š ๐Ÿš—

Blood Alcohol Concentration (BAC) Calculator

Calculate your estimated blood alcohol concentration based on drinks consumed, body weight, gender, and time since drinking began. Understand intoxication levels and legal limits.

๐Ÿ“‹ Quick Navigation

๐Ÿ“Š Enter your details to estimate your blood alcohol concentration! ๐Ÿท
in kilograms
hours
0-59 minutes
average is 0.015

๐Ÿท Alcohol Consumed

12oz/355ml bottles
5oz/150ml glasses
1.5oz/44ml shots
Your Estimated Blood Alcohol Concentration
0.000
%
CALCULATING...

BAC Level

โ€”
%

Intoxication Level

โ€”
status

Total Drinks

โ€”
standard drinks

Time Until Sober

โ€”
approx. hours

๐Ÿ“Š BAC Effects Reference

BAC Level (%) Drinks* Effects Status
0.00 - 0.03 0-1 No noticeable effects โœ… Sober
0.04 - 0.06 1-2 Slight relaxation, mood elevation โœ… Low Risk
0.07 - 0.09 2-3 Slight impairment, mild euphoria โš ๏ธ Moderate
0.10 - 0.12 3-4 Noticeable impairment, slowed reflexes โš ๏ธ High
0.13 - 0.15 4-5 Significant impairment, risk of accidents ๐Ÿšซ Very High
0.16 - 0.20 5-7 Severe intoxication, loss of coordination ๐Ÿšซ Dangerous
0.21 - 0.30 7-10 Extreme intoxication, memory loss possible ๐Ÿšซ Severe
0.31+ 10+ Life-threatening, medical attention needed ๐Ÿšซ Critical

*Average drink estimates for a 70kg / 154 lb person.

๐Ÿง  Understanding Blood Alcohol Concentration

What is BAC?

Blood Alcohol Concentration (BAC), also called Blood Alcohol Level (BAL), is a measurement of alcohol in your bloodstream expressed as a percentage. For example, a BAC of 0.08% means there are 0.08 grams of alcohol per 100 milliliters of blood. BAC is the most common way to measure alcohol intoxication or drunkenness.

How is BAC Measured?

Breath Test (Breathalyzer): Measures alcohol in exhaled breath and estimates BAC. Quick and non-invasive. Blood Test: Measures actual alcohol in blood. Most accurate method. Urine Test: Less common, lower accuracy. Saliva Test: Emerging technology, moderate accuracy.

Legal BAC Limits

United States (21+): 0.08% for driving, 0.04% for commercial drivers, 0.01% for drivers under 21. Canada & UK: 0.08% for driving. Australia: 0.05% for drivers. Many European countries: 0.05% for driving. Open Container Laws: Many jurisdictions prohibit open alcohol containers in vehicles regardless of driver's BAC.

Factors Affecting BAC

Body Weight: Heavier individuals have lower BAC from same alcohol amount due to greater water distribution. Gender: Females typically have higher BAC than males consuming same amount due to less body water. Food Consumption: Food slows alcohol absorption. Eating before/during drinking lowers BAC. Stomach Content: Empty stomach causes rapid absorption and higher BAC. Drink Type: Different drinks have different ABV (alcohol by volume) percentages. Time: BAC rises as you drink and falls as your body metabolizes alcohol.

๐Ÿ’ก Note: This calculator uses the Widmark formula for BAC estimation. Actual BAC may vary based on individual metabolism, medications, food, and other factors. Never drive if you've consumed alcohol.

โš ๏ธ Alcohol Effects & Health Impacts

Short-Term Effects by BAC Level

0.00-0.03%: No noticeable effects. 0.04-0.06%: Slight relaxation, mild mood elevation, no significant impairment. 0.07-0.09%: Slight impairment of balance and memory, mild euphoria, judgment starting to be affected. 0.10-0.12%: Noticeable impairment, slowed reaction time, decreased coordination.

Moderate to High Intoxication

0.13-0.15%: Significant impairment, blurred vision, loss of coordination, reduced inhibitions. 0.16-0.20%: Severe intoxication, difficulty standing or walking, slurred speech, poor judgment. 0.21-0.30%: Extreme intoxication, possible memory blackouts, confusion, poor motor control.

Dangerous & Critical Levels

0.31-0.40%: Severe intoxication, loss of consciousness risk, medical attention needed. 0.41%+: Life-threatening. Alcohol poisoning risk. Respiratory failure possible. Immediate medical emergency. Call emergency services.

Long-Term Health Effects

Regular excessive alcohol consumption can lead to liver disease, heart problems, brain damage, increased cancer risk, weakened immune system, and alcohol dependence (alcoholism). Short-term effects include dehydration, impaired judgment, increased accident risk, and hangovers.

โš ๏ธ Important Safety Notice: If someone has a BAC above 0.40%, shows signs of alcohol poisoning (unconsciousness, seizures, slow breathing), or you're unsure about their condition, call emergency services immediately. Do not attempt to "let them sleep it off." Alcohol poisoning is a medical emergency.

๐Ÿงฎ BAC Calculation Formulas

Widmark Formula

BAC % = [(A รท (P ร— r)) ร— 100] โˆ’ (ฮฒ ร— t)

Where:
A = Amount of alcohol consumed (in grams)
P = Person's body weight (in grams)
r = Gender-specific water distribution ratio
ฮฒ = Alcohol elimination rate (% per hour, โ‰ˆ 0.015)
t = Time elapsed (in hours)

Gender ratios (r):
Male: 0.68
Female: 0.55

Standard Drink Calculations

One Standard Drink (14g pure alcohol):
12 oz (355 ml) beer at 5% ABV
5 oz (148 ml) wine at 12% ABV
1.5 oz (44 ml) liquor at 40% ABV

Pure Alcohol in Drink = Volume (ml) ร— ABV% รท 100 ร— 0.789

Alcohol Metabolism

BAC Decrease = ฮฒ ร— Time Elapsed

Average elimination rate: 0.015% per hour
Time to Sobriety = Initial BAC % รท 0.015

Example: 0.10% BAC takes about 6.7 hours to eliminate
0.10 รท 0.015 = 6.67 hours

Example Calculation (Corrected)

Scenario: 70kg male, 3 beers in 2 hours

Step 1: Convert weight to grams
70 kg = 70,000 grams

Step 2: Calculate total alcohol in grams
3 beers ร— 14g = 42g pure alcohol

Step 3: Apply Widmark formula
Initial BAC % = [(42g รท (70,000g ร— 0.68)) ร— 100]
Initial BAC % = [(42 รท 47,600) ร— 100] = 0.088%

Step 4: Subtract metabolized alcohol
Final BAC % = 0.088% - (0.015 ร— 2 hours) = 0.058%

โ“ Frequently Asked Questions

Can I drive with any alcohol in my system? +
No. Even small amounts of alcohol impair judgment and reaction time. The legal limit of 0.08% in the US allows some impairment at the legal threshold. However, impairment begins at lower levels. The safest approach: don't drink and drive. Use designated drivers, taxis, or rideshare services.
How long does alcohol stay in your system? +
Alcohol is metabolized at approximately 0.015% BAC per hour (one standard drink per hour). Your body can't speed this up with coffee, cold showers, or exercise. A person with 0.10% BAC takes about 6-7 hours to reach sobriety. Blood tests can detect alcohol for 12-24 hours, urine tests for 12-48 hours.
Why do women get drunker than men? +
Women typically have less body water than men (55% vs 68% for water distribution), so the same amount of alcohol is distributed in less water, resulting in higher BAC. Additionally, women have less of the enzyme that breaks down alcohol (alcohol dehydrogenase), leading to slower metabolism.
Does food affect BAC? +
Yes, significantly. Food slows alcohol absorption into the bloodstream. Eating before or while drinking can lower your BAC by 20-30%. Empty stomach drinking causes rapid absorption and higher peak BAC. High-fat foods slow absorption more than carbohydrates or proteins.
Can I have "just one drink" and drive safely? +
Even one drink can impair your judgment and reaction time. Studies show measurable impairment begins at very low BAC levels. Safer option: consume zero alcohol if you're driving. The risks of impaired driving (accidents, injuries, deaths) far outweigh any drinking benefit.
What's the difference between BAC and breathalyzer results? +
Breathalyzers estimate BAC by measuring alcohol in exhaled breath. They assume a fixed breath-to-blood ratio. Blood tests measure actual BAC directly. Breathalyzers are convenient for roadside testing but slightly less accurate than blood tests. Factors like mouth alcohol or breath temperature can affect breathalyzer readings.
What should I do if I suspect alcohol poisoning? +
Call emergency services immediately. Signs include unconsciousness, seizures, slow breathing (fewer than 8 breaths per minute), irregular heartbeat, or extreme confusion. Never leave them alone. Place them on their side if unconscious to prevent choking. Provide information about what they consumed if possible.

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