Blood Alcohol Calculator (BAC) + Legal Limit by State

Alcohol consumed	42 g (3.0 standard drinks)
Peak if all absorbed at once	0.080%
Below 0.08% in about	now
Below 0.05% in about	0 min
Back to 0.00% in about	3 h 20 min

How the blood alcohol content calculator works

The calculator uses Widmark’s equation, the formula forensic toxicologists use to estimate blood alcohol concentration from the amount drunk, body weight, a body-water factor and time.^[1] Each step is shown in the result:

Alcohol consumed: fluid ounces × ABV × 0.789 g/mL. A U.S. standard drink holds 14 grams of pure alcohol: 12 oz of 5% beer, 5 oz of 12% wine or 1.5 oz of 40% spirits.^[2]
Distribution: grams ÷ (body weight in grams × r), where r is 0.68 for men and 0.55 for women, because women on average carry less body water per pound.
Elimination: minus about 0.015 percentage points for each hour since the first drink.

What counts as one U.S. standard drink (14 g of alcohol)
Drink	Typical strength	Size of one standard drink	Grams in a typical serving
Regular beer	5% ABV	12 fl oz	14 g (12 oz)
Craft IPA	7–9% ABV	about 8 fl oz	28 g (16 oz pint at 7.5%)
Wine	12% ABV	5 fl oz	25 g (9 oz restaurant pour)
Spirits	40% ABV (80 proof)	1.5 fl oz	14 g (one shot)

BAC chart by number of drinks and weight

The charts give estimated BAC one hour after starting, for standard drinks drunk quickly; values at or above 0.08% are over the adult driving limit in 50 states and DC except Utah, where the limit is 0.05%.

Estimated BAC (%), men, 1 hour after the first drink
Drinks	120 lb	140 lb	160 lb	180 lb	200 lb	240 lb
1	0.023	0.017	0.013	0.010	0.008	0.004
2	0.061	0.050	0.042	0.035	0.030	0.023
3	0.098	0.082	0.070	0.061	0.053	0.042
4	0.136	0.115	0.098	0.086	0.076	0.061
5	0.174	0.147	0.127	0.111	0.098	0.080
6	0.212	0.180	0.155	0.136	0.121	0.098

Estimated BAC (%), women, 1 hour after the first drink
Drinks	120 lb	140 lb	160 lb	180 lb	200 lb	240 lb
1	0.032	0.025	0.020	0.016	0.013	0.008
2	0.079	0.065	0.055	0.047	0.041	0.032
3	0.125	0.105	0.090	0.079	0.069	0.055
4	0.172	0.145	0.125	0.110	0.097	0.079
5	0.219	0.185	0.160	0.141	0.125	0.102
6	0.266	0.226	0.195	0.172	0.153	0.125

Legal limit by state

Every state makes it a crime to drive with a BAC of 0.08% or more (per se DUI), except Utah, which lowered its limit to 0.05% at the end of 2018.^[5]^[6] Lower federal standards apply to two groups: commercial drivers are prohibited from performing safety-sensitive functions at 0.04%,^[4] and federal highway funding requires every state to set a limit of 0.02% or less for drivers under 21.^[3] You can also be convicted of impaired driving below these numbers if alcohol affected your driving.

Per se blood alcohol limit for adult drivers by state
State	Limit	Statute
Alabama	0.08%	Ala. Code § 32-5A-191(a)(1)
Alaska	0.08%	Alaska Stat. § 28.35.030(a)(2)
Arizona	0.08%	Ariz. Rev. Stat. § 28-1381(A)(2)
Arkansas	0.08%	Ark. Code Ann. § 5-65-103(a)(2)
California	0.08%	Cal. Veh. Code § 23152(b)
Colorado	0.08%	Colo. Rev. Stat. § 42-4-1301(2)(a)
Connecticut	0.08%	Conn. Gen. Stat. § 14-227a(a)(2)
Delaware	0.08%	Del. Code Ann. tit. 21, § 4177(a)
District of Columbia	0.08%	D.C. Code §§ 50-2206.11, 50-2206.01
Florida	0.08%	Fla. Stat. § 316.193(1)(b)
Georgia	0.08%	O.C.G.A. § 40-6-391(a)(5)
Hawaii	0.08%	Haw. Rev. Stat. § 291E-61(a)(4)
Idaho	0.08%	Idaho Code § 18-8004(1)(a)
Illinois	0.08%	625 ILCS 5/11-501(a)(1)
Indiana	0.08%	Ind. Code § 9-30-5-1
Iowa	0.08%	Iowa Code § 321J.2
Kansas	0.08%	Kan. Stat. Ann. § 8-1567(a)
Kentucky	0.08%	Ky. Rev. Stat. § 189A.010(1)(a)
Louisiana	0.08%	La. R.S. 14:98(A)(1)(b)
Maine	0.08%	Me. Rev. Stat. tit. 29-A, § 2411(1-A)
Maryland	0.08%	Md. Code, Transp. § 21-902(a)(1)(ii)
Massachusetts	0.08%	Mass. Gen. Laws ch. 90, § 24(1)(a)(1)
Michigan	0.08%	Mich. Comp. Laws § 257.625(1)(b)
Minnesota	0.08%	Minn. Stat. § 169A.20, subd. 1(5)
Mississippi	0.08%	Miss. Code Ann. § 63-11-30(1)(c)
Missouri	0.08%	Mo. Rev. Stat. § 577.012
Montana	0.08%	Mont. Code Ann. § 61-8-1002(1)(b)
Nebraska	0.08%	Neb. Rev. Stat. § 60-6,196(1)(b)
Nevada	0.08%	Nev. Rev. Stat. § 484C.110(1)(b)
New Hampshire	0.08%	N.H. Rev. Stat. § 265-A:2(I)(b)
New Jersey	0.08%	N.J. Stat. Ann. § 39:4-50(a)
New Mexico	0.08%	N.M. Stat. Ann. § 66-8-102(C)
New York	0.08%	N.Y. Veh. & Traf. Law § 1192(2)
North Carolina	0.08%	N.C. Gen. Stat. § 20-138.1(a)(2)
North Dakota	0.08%	N.D. Cent. Code § 39-08-01(1)(a)
Ohio	0.08%	Ohio Rev. Code § 4511.19(A)(1)(b)
Oklahoma	0.08%	Okla. Stat. tit. 47, § 11-902(A)(1)
Oregon	0.08%	Or. Rev. Stat. § 813.010(1)(a)
Pennsylvania	0.08%	75 Pa. Cons. Stat. § 3802(a)(2)
Rhode Island	0.08%	R.I. Gen. Laws § 31-27-2(b)(1)
South Carolina	0.08%	S.C. Code Ann. § 56-5-2933
South Dakota	0.08%	S.D. Codified Laws § 32-23-1(1)
Tennessee	0.08%	Tenn. Code Ann. § 55-10-401(2)
Texas	0.08%	Tex. Penal Code §§ 49.01(2)(B), 49.04
Utah	0.05%	Utah Code § 41-6a-502(1)(a)
Vermont	0.08%	Vt. Stat. Ann. tit. 23, § 1201(a)(1)
Virginia	0.08%	Va. Code § 18.2-266(i)
Washington	0.08%	Wash. Rev. Code § 46.61.502(1)(a)
West Virginia	0.08%	W. Va. Code § 17C-5-2
Wisconsin	0.08%	Wis. Stat. § 346.63(1)(b)
Wyoming	0.08%	Wyo. Stat. § 31-5-233(b)(i)

Jurisdictions below 0.08%: Utah.

How long to sober up

Alcohol leaves the blood at roughly 0.015% per hour, and nothing speeds it up: coffee, water, food after drinking and cold showers do not change the elimination rate. From 0.08% it takes about 5 hours to reach zero, and from 0.16% about 11 hours, which is why people who drank late at night can still be over the limit the next morning. The calculator shows the time to 0.08%, 0.05% and 0.00% for your numbers.

Why the estimate can be wrong

Absorption: the formula assumes all alcohol is absorbed; on a full stomach, BAC rises more slowly and peaks lower, on an empty stomach faster.
Body composition: r varies between people. The 0.68 and 0.55 averages were measured decades ago and can be far off for very lean or very heavy people.^[1]
Elimination: real rates range from about 0.010% to 0.025% per hour.
Pour size: home and bar pours are often larger than a standard drink.

For these reasons a calculator can never tell you that you are safe to drive. If you face a DUI charge, the deadlines are criminal ones; see what a statute of limitations is and the statute of limitations by state. If a drunk driver injured you, the car accident settlement calculator estimates the claim, and the personal injury settlement calculator covers other injuries.

Frequently asked questions

How do you calculate blood alcohol content?

With Widmark’s formula: BAC (%) = grams of alcohol ÷ (body weight in grams × r) × 100 − 0.015 × hours since drinking began, where r is about 0.68 for men and 0.55 for women. One U.S. standard drink contains 14 grams of alcohol.

How many drinks does it take to reach 0.08?

For a 170-lb man, about 4 standard drinks in an hour; for a 140-lb woman, about 3. Smaller people, stronger drinks and drinking on an empty stomach reach it sooner. The chart on this page shows other weights.

What is the legal blood alcohol limit?

0.08% for drivers 21 and older in every state except Utah (0.05%); 0.04% for commercial drivers; and 0.02% or less for drivers under 21 under the federal zero-tolerance requirement.

How long does it take for BAC to go down?

About 0.015 percentage points per hour, so roughly 5 hours from 0.08% to zero. Coffee, water or a cold shower do not speed this up.

Sources

Widmark’s equation (breath test program training material) · Washington State Patrol, Breath Test Program, March 7, 2002
What is a standard drink? · National Institute on Alcohol Abuse and Alcoholism (NIH), checked November 2026
23 U.S.C. § 161: zero tolerance blood alcohol concentration for minors · U.S. Code, GovInfo (U.S. Government Publishing Office), current through November 2026
49 CFR § 382.201: alcohol concentration (commercial drivers, 0.04) · Electronic Code of Federal Regulations, current through November 2026
Utah Code § 41-6a-502(1)(a): per se blood alcohol limit · Utah (official), checked November 2026
Cal. Veh. Code § 23152(b): per se blood alcohol limit · California (official), checked November 2026

Blood alcohol calculator