In most U.S. states, the legal alcohol limit for driving is 0.08% BAC. But alcohol may affect your functioning before you reach this limit.
Alcohol affects everyone differently. Some people seem unfazed after a night of drinking, while for others, one glass can be enough to take away judgment and motor skills.
But just because you don’t see the visible effects of alcohol, it doesn’t mean you aren’t impaired. As your blood alcohol concentration (BAC) rises, so does your loss of ability.
Blood alcohol level charts can help you understand the effects of drinking based on your weight and sex. The charts can also help you plan ahead if alcohol is on the menu.
The National Highway Traffic Safety Administration (NHTSA) uses a BAC standard drink measurement of
Here’s the equivalent of one standard drink based on the type of alcohol, serving size, and alcohol percentage:
Intoxication levels depend on how quickly you drink. Because of this, approximately 0.015% can be subtracted for every hour that passes between beverages.
The following charts show how your blood alcohol levels change as you consume alcohol. The BAC is measuring the amount of alcohol within a 30- to 70-minute period.
As the current science has only been conducted on cisgender males and females, transgender or intersex individuals may be safer following the most conservative recommendations for their weight range.
Consider downloading a BAC app like DrinkControl or AlcoDroid for your phone to help track your BAC as you drink.
Who you gonna call?
When it comes to driving, most U.S. states place the legal limit at
If you or a friend has consumed too much alcohol to safely operate a vehicle, you can arrange for a designated driver through national services like:
If you’re at a bar, many facilities keep local listings on hand to help you arrange transport if you cannot do it yourself. Don’t be afraid to ask your server or bartender for assistance arranging a commercial driver ― they also want to make sure you get home safely.
The symptoms of impairment can start as soon as you have a drink and may become worse the faster you drink.
| BAC level | Standard effects |
|---|---|
| 0.02 | • muscle relaxation • altered mood • increased body warmth • decline in visual function • diminished capacity to multitask • loss of judgment |
| 0.05 | • loss of fine motor control • exaggerated behavior • reduced coordination • lowered reaction time • impaired judgment • low alertness • heightened mood • lack of inhibition |
| 0.08 | • small and large motor function decline • difficulty hearing, seeing, speaking, and coordination • short-term memory loss • inability to concentrate • impaired perception • reduced cognitive processing speed |
| 0.10 | • noticeable lack of reaction time • slurred speech • slowed thinking • lack of coordination |
| 0.15+ | • major loss of motor control • little or no balance • severe attention and reaction deficits • inability to cognitively process sounds or visuals • nausea or vomiting |
Safety is the number one priority when it comes to drinking alcohol, and driving is just one well-known area of risk. Even when you’re at home, too much drinking can compromise your physical health, resulting in alcohol poisoning or death.
Understanding more about alcohol consumption can help you make the best choices when you drink.
Determining when your alcohol level is too high depends on what you’re assessing it for.
Too high for driving, for example, is a number regulated by your state. This is 0.08% in all U.S. states except for Utah, where it’s 0.05%. But that doesn’t mean it’s safe to drive if you’re below those numbers.
The National Institute on Alcohol Abuse and Alcoholism (NIAAA) states that any amount of alcohol is “too much” when you’re:
- pregnant
- under the legal drinking age
- planning on driving
- at an increased risk of alcohol-related cancers
- living with certain chronic medical conditions
- taking medications
If you’re wondering when alcohol becomes toxic to your system, a BAC of more than 0.40% can result in respiratory depression, coma, and even death.
A 0.08 BAC equals 0.08%, not 8%, alcohol volume.
BAC is measured by grams of alcohol per deciliter of blood, or per 100 milliliters (mL) of blood. This means for every 100 mL of blood, there are 0.08 grams of alcohol.
The point at which you reach 0.08% BAC depends on many factors, such as:
- your sex
- your weight
- how many drinks you have
- how quickly you drink
- how much food is in your stomach
On average, for a 140-pound male, this is around 3 standard drinks. For a 140-pound female, it’s between 2 to 3 standard drinks.
Healthcare organizations consider moderate drinking levels to be:
- Men: 2 drinks or less per day
- Women: 1 drink or less per day
However, “safe” alcohol consumption doesn’t mean there are health benefits. A glass of wine for dinner may have some antioxidants, but the benefits don’t outweigh the negative impacts of alcohol on your body.
In general, no amount of alcohol is good for your health.
Changing your relationship with alcohol
Whether you want to find ways to politely decline drinking invitations or are looking for guidance on managing alcohol use disorder, help is available.
You can find quitting resources by visiting:
A blood alcohol level chart can be a useful tool when your plans include drinking. Even if you don’t feel impaired, the chart can show you what subtle effects might be happening.
For most people, consuming 2 to 3 drinks in 1 hour can impair you past the legal limit for driving. However, it’s important to note that any alcohol in your system will impair your cognitive and physical functions.
Ultimately, consuming alcohol can pose a risk to your health and the health of others. Planning ahead for designated drivers, keeping track of your alcohol intake, and finding ways to drink less can all help make your nights out safer.