BAC Chart: Blood Alcohol Level by Drinks, Weight, and Time
A BAC chart helps explain how blood alcohol concentration can change by drink count, body weight, sex, and time. It is a learning aid, not a driving, legal, medical, or test-clearance tool.
Editorial note
This educational page is maintained by EtGCalc and reviewed against published EtG research, SAMHSA guidance, and our calculator methodology. It does not provide medical or legal advice.
Quick answer
BAC means blood alcohol concentration. In the United States, a BAC of 0.080% is a common adult per se driving limit, but impairment and legal risk can exist below that level. Use the chart below to understand ranges, then use the BAC Calculator for a scenario-specific estimate.
BAC Level Chart
These ranges are simplified educational categories. Actual measured BAC can differ from an estimate because of drinking pattern, food, body composition, device calibration, and timing.
| BAC range | Plain-English meaning | Important context |
|---|---|---|
| 0.000% | No measurable BAC in the estimate | A calculator estimate of zero is not the same as a lab or device measurement. |
| 0.010% - 0.029% | Low but measurable estimate | Some effects can occur below common legal limits, especially with fatigue or medications. |
| 0.030% - 0.049% | Measurable alcohol level | Judgment, attention, and coordination may be affected even when someone feels normal. |
| 0.050% - 0.079% | Elevated BAC estimate | Risk increases. Do not use an online chart to decide whether driving or work is safe. |
| 0.080%+ | At or above the common U.S. adult per se driving limit | Legal limits vary by person, license type, jurisdiction, and situation. |
Estimated BAC by Weight and Standard Drinks
This table shows rough peak BAC ranges before time-based metabolism. The lower and upper values reflect common Widmark distribution-factor differences. It does not account for hours elapsed, food, drink speed, or unusually large pours.
| Body weight | 1 standard drink | 2 standard drinks | 3 standard drinks |
|---|---|---|---|
| 120 lb | 0.032% - 0.040% | 0.064% - 0.080% | 0.096% - 0.120% |
| 150 lb | 0.026% - 0.032% | 0.051% - 0.064% | 0.077% - 0.096% |
| 180 lb | 0.021% - 0.027% | 0.043% - 0.053% | 0.064% - 0.080% |
| 210 lb | 0.018% - 0.023% | 0.037% - 0.046% | 0.055% - 0.069% |
Checking current breath alcohol?
A chart is only an estimate. If your question is current breath alcohol, a consumer breathalyzer is closer to that question than an EtG urine strip. It still cannot guarantee safety, legality, or an official result.
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What Counts as One Standard Drink?
NIAAA defines a U.S. standard drink as any beverage containing about 0.6 fluid ounces, or 14 grams, of pure alcohol. Serving size alone is not enough; ABV matters.
Regular beer
Serving: 12 fl oz
Alcohol: About 5% ABV
Table wine
Serving: 5 fl oz
Alcohol: About 12% ABV
Distilled spirits
Serving: 1.5 fl oz
Alcohol: About 40% ABV
BAC Chart vs BAC Calculator vs EtG Testing
BAC chart
Best for: Best for understanding broad ranges and why weight and drink count matter.
Limit: Not personalized enough for time, sex, and exact drink strength.
BAC calculator
Best for: Best for scenario-specific current BAC estimates using inputs.
Limit: Still an estimate, not a calibrated measurement.
EtG urine testing
Best for: Best for longer-window alcohol metabolite questions.
Limit: Does not measure current impairment or current BAC.
Do not use BAC charts as clearance advice
BAC charts and calculators can be wrong in either direction. They should not be used to decide whether to drive, operate equipment, work, take a test, or make a legal decision.
Frequently Asked Questions
What is a BAC chart?
A BAC chart is a reference table that helps explain estimated blood alcohol concentration ranges by drink count, body weight, and time. It is educational context, not a measured result.
Can a BAC chart tell me if I am safe to drive?
No. A BAC chart cannot determine safety, legality, impairment, or actual alcohol level. If you have been drinking, do not use a chart or calculator as driving clearance.
Why does body weight change BAC?
The same amount of alcohol is distributed differently depending on body size, body water, sex, drinking speed, food, and individual metabolism. That is why two people can have different BAC estimates after the same number of drinks.
Is BAC the same as EtG?
No. BAC refers to current alcohol in blood or breath. EtG is a urine alcohol metabolite marker that can remain detectable after alcohol itself has been metabolized.
Related Reading
How Long Alcohol Stays in Blood
Understand blood alcohol timing and BAC detection context.
Alcohol Detection Times by Test Type
Compare breath, blood, urine ethanol, EtG urine, and hair testing windows.
BAC Calculator
Estimate current BAC using drinks, weight, sex, and elapsed time.
How Long Alcohol Stays on Breath
Understand breath alcohol timing and breathalyzer context.
Breathalyzer Test Guide
Learn what breath tests measure and when a home breathalyzer is useful.
EtG vs BAC
Compare current alcohol testing with longer-window urine metabolites.
EtG Urine Test Calculator
Use this when your question is urine EtG detection and cutoffs.
References
Medical & Legal Disclaimer
Not Medical Advice
EtGCalc does not provide diagnosis, treatment, or medical advice. Talk with a qualified healthcare provider about alcohol use, metabolism, testing concerns, or recovery.
Not Legal Advice
EtG testing can affect probation, custody, licensing, and employment decisions. Consult a licensed attorney or your testing program for legal questions.
If You Need Support
In the United States, SAMHSA's National Helpline is 1-800-662-4357. It is free, confidential, and available 24/7.
Calculator output is an estimate, not a test prediction. Individual metabolism, hydration, kidney function, genetics, specimen handling, and lab cutoff policy can change real results. See our methodology and sources.