Here are two sex-weighted charts as a method of calculating an approximate BAC level…

ALCOHOL IMPAIRMENT CHART
FEMALES

APPROXIMATE BLOOD ALCOHOL PERCENTAGE
Drinks
*
BODY WEIGHT IN POUNDS
EFFECT ON PERSON
90100120140160180200220240
0
.00.00.00.00.00.00.00.00.00
ONLY SAFE DRIVING LIMIT
1
.05.05.04.03.03.03.02.02.02
IMPAIRMENT BEGINS.
2
.10.09.08.07.06.05.05.04.04
DRIVING SKILLS SIGNIFICANTLY AFFECTED.
3
.15.14.11.11.09.08.07.06.06
4
.20.18.15.13.11.10.09.08.08
LEGALLY INTOXICATED.CRIMINAL PENALTIES IN ALLSTATES
** 

5
.25.23.19.16.14.13.11.10.09
6
.30.27.23.19.17.15.14.12.11
7
.35.32.27.23.20.18.16.14.13
8
.40.36.30.26.23.20.18.17.15
9
.45.41.34.29.26.23.20.19.17
10
.51.45.38.32.28.25.23.21.19

Subtract .01% for each 40 minutes of drinking.
* One drink is equal to 1¼ oz. of 80-proof liquor, 12 oz. of beer, or 4 oz. of table wine.
ALCOHOL IMPAIRMENT CHART
MALES

APPROXIMATE BLOOD ALCOHOL PERCENTAGE
Drinks
*
BODY WEIGHT IN POUNDS
EFFECT ON PERSON
100120140160180200220240
0
.00.00.00.00.00.00.00.00
ONLY SAFE DRIVING LIMIT
1
.04.03.03.02.02.02.02.02
IMPAIRMENT BEGINS.
2
.08.06.05.05.04.04.03.03
3
.11.09.08.07.06.06.05.05
DRIVING SKILLS SIGNIFICANTLY AFFECTED.
4
.15.12.11.09.08.08.07.06
5
.19.16.13.12.11.09.09.08
LEGALLY INTOXICATED.

CRIMINAL PENALTIES IN ALL STATES
**
6
.23.19.16.14.13.11.10.09
7
.26.22.19.16.15.13.12.11
8
.30.25.21.19.17.15.14.13
9
.34.28.24.21.19.17.15.14
10
.38.31.27.23.21.19.17.16

Subtract .01% for each 40 minutes of drinking.
* One drink is equal to 1¼ oz. of 80-proof liquor, 12 oz. of beer, or 4 oz. of table wine.