BAC Calculator

If you’ve been arrested for a DUI in Pennsylvania, you may be asked to take a breathalyzer test. Even if you haven’t been stopped for DUI, you may want to determine your approximate blood alcohol level. If you are stopped for DUI, you’ll be asked to perform several field sobriety tests. These are done to help the police officer quickly analyze if you are possibly intoxicated. Some of these tests include following a light with your eyes, standing on one leg, and walking a straight line. If the police have reason to believe you are intoxicated they may ask you to take a breathalyzer, blood, or urine test. These tests determine the blood alcohol level.


Fluid Ounces ConsumedPercent Alcohol
Your Weight (Lbs)Hours Consuming Drink
BAC Percentage
BAC Analysis


What is Blood Alcohol Content?
Blood alcohol content (BAC) is the concentration of alcohol in the bloodstream. When you drink an alcoholic beverage, the alcohol enters your bloodstream. The more you drink, the higher the concentration of alcohol. In Pennsylvania, the legal BAC level is 0.08 percent for adults over the age of 21. If you are driving with a BAC of over 0.08 percent you can be considered legally over the limit and may be charged with DUI (driving under the influence). A BAC test measures the amount of alcohol in the bloodstream. For example, a BAC of 0.05 percent means that the person has a concentration of alcohol of .05 grams for every 100 ml of blood.

What Can Have an Effect on Blood Alcohol Level?
There are several factors that can affect your BAC. Some of these factors include:

  • Body size – a person who is smaller and weighs less will have a higher BAC than a larger person. This occurs because the alcohol is more concentrated in a smaller-sized body.
  • Body fat – Body fat doesn’t absorb alcohol as readily so a person with more body fat will tend to have a higher BAC.
  • Empty stomach – Drinking on an empty stomach will increase the BAC because the body immediately allows the alcohol to enter the bloodstream. A full stomach absorbs some of the alcohol and thus lowers the BAC.
  • Gender – Women who drink the same amount as men will almost always have a higher BAC, primarily because of their size.

How to Determine Blood Alcohol Content (BAC)
You can make a rough estimate of your BAC. When determining your BAC, remember that one drink is equal to one 12-ounce beer, one 5-ounce glass of wine, or one 1.5-ounce shot of liquor. The alcohol content in beer is approximately 4 to 4.5 percent, wine is 15-20 percent and liquor is 30-50 percent per shot. You will need to know your weight, the number of fluid ounces of alcohol consumed, the percentage of alcohol in the drinks you had, and the length of time, in hours, that you spent drinking. Plug these values into the BAC calculator to find out what your approximate BAC is. Note that the calculator is intended only as a tool and may differ from an actual breathalyzer or blood test.

What to do when Your BAC is too High
The first thing to keep in mind is that you are legally required to submit to a BAC test. If you refuse to take the test (breathalyzer or blood) you will be facing additional charges and penalties in addition to DUI. The best thing you can do if you have been charged with DUI is to talk to an experienced DUI attorney as soon as possible. Often there are several charges – some of which may be dropped if an attorney is involved immediately. An attorney will work to determine what happened and to develop a compelling defense strategy.

Call the Law Offices of Steven E. Kellis today for a free consultation (215) 940-1200 or complete our contact form. Our phone is answered 24 hours a day.