BAC chart by body weight and number of drinks
These two printable tables show estimated blood alcohol concentration one hour after drinking, for men and for women, across body weights from 100 to 240 lb and one to six standard drinks. Every figure comes from the Widmark formula with average values, so read each cell as a rough guide to how alcohol scales with weight and quantity, not as a measurement of anyone in particular.
Per se driving limits in the US, % BAC
What these numbers can and cannot tell you
This is an estimate. It cannot tell you whether you are safe or legal to drive. If you have been drinking, do not drive.
A real person can land well above the figure in their row. Pour size, drink strength, food, body composition, medication and the speed of drinking all move the result, and none of them fit in a printed grid.
How this BAC chart was calculated
Each cell uses one US standard drink of 14 grams of pure alcohol, which is about 12 oz of 5% beer, 5 oz of 12% wine or 1.5 oz of 40% spirits. The grams are divided by body weight in grams times a distribution factor r, which stands for the share of the body where alcohol dissolves. The chart uses 0.68 for men and 0.55 for women, the classic Widmark averages.
The result is the peak level as if all drinks were absorbed at once. From that peak the chart subtracts 0.015, the average amount an adult liver clears in one hour. So a cell answers this question: roughly what would an average person of this sex and weight read one hour after starting, if the drinks were taken together.
- Standard drink of 14 grams of alcohol
- Distribution factor 0.68 for men and 0.55 for women
- One hour of elimination at about 0.015 per hour
- Figures rounded to three decimals
BAC chart for men one hour after drinking
Estimated BAC by body weight (rows) and standard drinks (columns), distribution factor 0.68.
| Body weight | 1 drink | 2 drinks | 3 drinks | 4 drinks | 5 drinks | 6 drinks |
|---|---|---|---|---|---|---|
| 100 lb | 0.030 | 0.076 | 0.121 | 0.167 | 0.212 | 0.257 |
| 120 lb | 0.023 | 0.061 | 0.098 | 0.136 | 0.174 | 0.212 |
| 140 lb | 0.017 | 0.050 | 0.082 | 0.115 | 0.147 | 0.180 |
| 160 lb | 0.013 | 0.042 | 0.070 | 0.098 | 0.127 | 0.155 |
| 180 lb | 0.010 | 0.035 | 0.061 | 0.086 | 0.111 | 0.136 |
| 200 lb | 0.008 | 0.030 | 0.053 | 0.076 | 0.098 | 0.121 |
| 220 lb | 0.006 | 0.026 | 0.047 | 0.068 | 0.088 | 0.109 |
| 240 lb | 0.004 | 0.023 | 0.042 | 0.061 | 0.080 | 0.098 |
BAC chart for women one hour after drinking
Estimated BAC by body weight (rows) and standard drinks (columns), distribution factor 0.55.
| Body weight | 1 drink | 2 drinks | 3 drinks | 4 drinks | 5 drinks | 6 drinks |
|---|---|---|---|---|---|---|
| 100 lb | 0.041 | 0.097 | 0.153 | 0.209 | 0.266 | 0.322 |
| 120 lb | 0.032 | 0.079 | 0.125 | 0.172 | 0.219 | 0.266 |
| 140 lb | 0.025 | 0.065 | 0.105 | 0.145 | 0.185 | 0.226 |
| 160 lb | 0.020 | 0.055 | 0.090 | 0.125 | 0.160 | 0.195 |
| 180 lb | 0.016 | 0.047 | 0.079 | 0.110 | 0.141 | 0.172 |
| 200 lb | 0.013 | 0.041 | 0.069 | 0.097 | 0.125 | 0.153 |
| 220 lb | 0.011 | 0.036 | 0.062 | 0.087 | 0.113 | 0.138 |
| 240 lb | 0.008 | 0.032 | 0.055 | 0.079 | 0.102 | 0.125 |
How to read the chart step by step
Find the row closest to your body weight, then move across to the number of standard drinks you had. If your weight falls between two rows, take the lighter row, which gives the higher and more cautious figure.
Count drinks honestly in standard units. A pint of 6.5% craft beer is close to two standard drinks, a generous 8 oz glass of 13% wine is about one and three quarters, and a cocktail with two shots is two. Undercounting is the most common way people misread a chart like this.
Adjust for time. Each cell already includes one hour of elimination. For every further hour since you started, subtract roughly 0.015, or less if you want the cautious answer. If you finished your last drink only minutes ago, your level may still be rising, so the real peak can arrive later than the chart suggests.
- Pick your weight row, rounding down when in doubt
- Convert what you drank into standard drinks
- Read the cell, then subtract about 0.015 for each extra hour
- Treat the figure as the middle of a wide range
Typical effects at each BAC level
Alcohol affects people differently, and tolerance can hide signs without lowering the actual level in the blood. The bands below follow the general descriptions published by highway safety agencies and medical references.
| BAC band | Typical effects |
|---|---|
| 0.02 to 0.03 | Mild relaxation, slight warmth, some loss of judgment and a reduced ability to do two things at once |
| 0.04 to 0.06 | Lowered inhibition, exaggerated behavior, weaker coordination and slower response to sudden events |
| 0.07 to 0.09 | Reduced balance, speech, vision and reaction time, poorer self control and memory |
| 0.10 to 0.12 | Clear loss of coordination, slurred speech, slowed thinking and poor control of speed and lane position |
| 0.13 to 0.15 | Major loss of balance and motor control, blurred vision, anxiety or restlessness may begin |
| 0.16 to 0.20 | Strong impairment, nausea and vomiting are common, a person may appear disoriented |
| 0.25 and above | Severe impairment, risk of losing consciousness, choking and alcohol poisoning |
| 0.30 and above | Possible stupor, danger to breathing and heart function, a medical emergency |
If someone cannot be woken, breathes slowly or irregularly, or has pale or bluish skin after heavy drinking, call 911 and stay with them.
Where the legal lines fall on the chart
For most adult drivers in the United States the per se limit is 0.08. Utah sets it at 0.05, commercial drivers face 0.04, and drivers under 21 fall under zero tolerance rules, usually 0.02 or lower. On the men's chart, three drinks pushes a 140 lb man past 0.08 within the first hour. On the women's chart, two drinks bring a 120 lb woman to the edge of 0.08 and a 100 lb woman well past it.
Impairment does not start at a legal number. The effects table shows that judgment and divided attention decline in the lowest bands. Our legal alcohol limit page explains the rules in plain terms, and the bac legal limit table lists them state by state.
When a calculator fits better than a chart
A printed grid has to fix the time, the drink size and the weight steps. The interactive bac calculator lets you enter real volumes and strengths and returns a range, and the bac calculator over time shows how a starting estimate falls hour by hour until it reaches about 0.00.
A chart and a calculator still only predict. A breath tester reports what is in your breath right now. If you want that reading, compare models in our best breathalyzer ranking or look at the alcohol specific fuel cell breathalyzer options.
A calculator only estimates. To measure, a fuel cell breathalyzer reads your actual breath.
BAC chart questions
Why does the women's chart show higher numbers?
On average women carry a lower share of body water at the same weight, so the same alcohol is less diluted, which the chart reflects with a distribution factor of 0.55 instead of 0.68.
What counts as one standard drink in this chart?
One standard drink contains 14 grams of pure alcohol, roughly 12 oz of 5% beer, 5 oz of 12% wine or 1.5 oz of 40% spirits.
Why does the chart use one hour after drinking?
One hour is a practical reference point that includes some elimination, and you can subtract about 0.015 for each further hour to follow the decline.
Is the BAC chart accurate for me?
It describes an average person, so your real level can be noticeably higher or lower depending on food, body composition, pour size and health.
Can I use the chart to decide whether I can drive?
No, the chart gives estimates that cannot tell you whether you are safe or legal to drive, and if you have been drinking you should not drive.
What is the difference between this chart and a breathalyzer reading?
The chart predicts a level from averages, while a breathalyzer measures alcohol in your breath, and our breathalyzer test guide explains how to take a clean reading.