Blood Alcohol Concentration (BAC) Chart: How Many Drinks Does It Take to Be Over the Limit?

In all 50 states, it’s illegal to drive with a BAC of .08% or more (.05% or more in Utah). Lots of factors affect blood alcohol concentration (BAC), and a person's BAC is generally always in a state of rising or falling. However, the most influential considerations include:

• number of drinks
• sex
• body weight, and
• amount of time spent drinking.

What Is BAC?

“BAC” stands for “blood alcohol concentration,” sometimes called “blood alcohol content” or “blood alcohol level.” Basically, BAC is a measurement of the amount of alcohol in your blood. A driver's BAC is one of the main factors that determine the penalties the driver will face.

The two most common ways police measure the amount of alcohol in a suspect’s system are blood and breath tests. Blood tests require a phlebotomist or other medical personnel to take a blood sample. Breath tests give instantaneous results, and officers can administer breath tests without the assistance of medical personnel.

Estimating BAC: Limitations

The chart below provides only an estimate of what a person’s BAC might be. You shouldn’t rely on the accuracy of this estimate in making decisions like whether to drive.

There are lots of factors the chart doesn’t account for that can affect BAC or how impaired someone is. The chart doesn’t address, for instance, food eaten, medications taken, or amount of sleep. Plus, everyone absorbs and metabolizes alcohol at different rates.

If you’ve been drinking—regardless of how much—it’s best not to get behind the wheel.

How to Use the Chart

The chart below gives BAC estimates based on sex, number of drinks of specific sizes and alcohol content, and body weight. (It’s based on a similar chart found in the California Driver Handbook.)

To estimate a person’s BAC:

1. Find the BAC value corresponding to the person’s sex, body weight, and number of drinks consumed.
2. Subtract .01% from the BAC for every 40 minutes that have passed since the person started drinking.

For example, suppose a 120-pound woman had three glasses of wine in 80 minutes. From the chart, the BAC would be .17%. But because 80 minutes have passed, we need to subtract .02% (.01% for each 40 minutes). The woman’s estimated BAC would then be .15%.

How BAC Affects the Likelihood of a DUI Conviction

Most states have at least two DUI-related crimes: driving under the influence of drugs or alcohol and driving with a prohibited BAC. "Driving under the influence" generally means operating a vehicle while impaired. If the prosecution can show your driving was affected by alcohol or drugs, then you can be convicted with a BAC that’s less than the legal limit—or with no BAC at all.

Driving with a prohibited BAC is also called a “per se” DUI. It’s illegal to drive with a BAC of .08% or more (.05% or more in Utah). And the BAC limit is often lower for drivers under 21 and commercial vehicle drivers.

In 2015, we surveyed readers in different parts of the country who had been arrested for first-offense DUI to learn how their BAC level affected the outcome of their arrest. As with the above chart, you shouldn't decide whether or not to drive based on this survey. Any drinking can put you at risk for a DUI conviction, and the likelihood of a conviction increases as your BAC goes up.

BAC Under .08%

Of the survey respondents who had an alleged BAC under .08%, 70% “got off”—meaning they were found not guilty, the charges were dropped, or the prosecution didn’t file charges. Only 20% of those with a BAC under .08% were convicted of a DUI—the rest were convicted of non-DUI offenses like reckless driving or wet reckless.

Of those with a BAC less than .08% who pleaded guilty or were convicted after trial, none were sentenced to jail, house arrest, or even community service. Their cases resolved with either probation or diversion (a form of sentencing that allows the defendant to avoid a conviction on the record).

BAC Between .08% and .14%

Not surprisingly, survey respondents who had a reported BAC of anywhere from .08% to .14% fared significantly worse. Among these people, only 16% were found not guilty or saw their charges dismissed, and 23% pleaded guilty to a lesser offense. The remaining 61% ended up with a DUI conviction.

As to sentencing, 48% in readers at this BAC level were placed on probation. Only 3% went to jail.

BAC of .15% or Higher

You may have noticed a trend by now, making it easy to believe that 0% of our readers who had a BAC of .15% or higher were found not guilty or had their charges dropped. Only 15% were able to plead guilty to a lesser offense. The vast majority of readers in this range, 85%, ended up with a DUI conviction.

The majority (63%) of defendants at or over .15% were placed on probation and 14% were sentenced to jail or prison.

Talk to a DUI Lawyer

The circumstances of each case are unique, and everyone absorbs and metabolizes alcohol differently. Again, if you've been drinking at all or taking drugs of any kind, it's best not to get behind the wheel.

If you've been arrested for DUI, get in contact with a qualified DUI attorney. An experienced DUI lawyer can review the facts of your case and potentially can work with an expert toxicologist to challenge the chemical test results.