DUI vs DWI: what the terms mean, state by state

People arrive at this question for one of two reasons. Either they have just been charged and want to know whether they got the worse of the two, or they read something online and cannot tell whether it applies where they live. Both are answerable, but only after one thing is clear: impaired driving is state law, and each state’s code gives its own answer.

Breath testing is where the acronyms stop mattering and the numbers start. Every state code read for this page that writes a per se number for adult non-commercial drivers uses 0.08, whatever it calls the offense — Utah uses 0.05.

The short answer

DUI stands for driving under the influence. DWI stands for driving while intoxicated — or, in Minnesota’s statute, driving while impaired. In most of the states read for this page only one of those terms names the offense. If you are charged in California it is a DUI because that is what the Vehicle Code’s section 23152 describes; if you are charged in Texas it is a DWI because Penal Code section 49.04 is “driving while intoxicated”. Nothing else follows from the choice of word.

In five of the states read here, two or more terms point at different offenses. In those states the difference is real, and getting it backwards can lead you to read the wrong penalty range for your own case. Those states are the reason this page exists.

The same diagram as a table

The branch diagram as a table: which pattern a state follows, and what the terms mean inside that pattern.

Pattern	States	What the terms mean there
One name	DUI: CA, AZ, FL, GA, WA. DWI: MN (statute says “driving while impaired”). OWI: IA. OUI: ME. DUII: OR. Virginia’s heading says “while intoxicated” and its text “under the influence”.	The acronym is only the word that legislature happened to use.
Two or more names — split by severity	Maryland	“Under the influence” is the more serious; “impaired” is the lesser.
Two or more names — split by age	Texas	DWI covers every driver; DUI is a separate under-21 offense.
Two or more names — split by degree	New York, Colorado	The lesser charge is DWAI, and it means different things in each.
Two or more names — split by proof	South Carolina	DUI is impairment; DUAC is 0.08 or more, a separate offense.

Georgia is read from a 2024 reproduction of its code; every other state shown was read in its own code or a reproduction linking it.

What a DUI or DWI is, in the statutes’ words

Almost every statute read here defines the offense two ways at once: by what the alcohol or drug did to the driver, and by a number. Either one is enough.

• Texas defines “intoxicated” as “not having the normal use of mental or physical faculties by reason of the introduction of alcohol, a controlled substance, a drug, a dangerous drug, a combination of two or more of those substances, or any other substance into the body”, or “having an alcohol concentration of 0.08 or more” (Tex. Penal Code § 49.01(2).)
• Florida requires the driver to be under the influence “to the extent that the person’s normal faculties are impaired”, or to have a blood- or breath-alcohol level of 0.08 or more, while driving or in actual physical control of a vehicle (Fla. Stat. § 316.193(1).)
• South Carolina sets the impairment bar in words — faculties “materially and appreciably impaired” — and puts the number in a separate offense, driving with an unlawful alcohol concentration of 0.08 or more (S.C. Code §§ 56-5-2930(A), 56-5-2933(A).)
• Colorado sets its lower offense at impairment “to the slightest degree”, so that the person is less able than usual to exercise clear judgment, physical control or due care (C.R.S. § 42-4-1301(1)(g).)
• New York splits it by subdivision: 0.08 or more is DWI per se, “an intoxicated condition” is common-law DWI, and ability “impaired by the consumption of alcohol” is DWAI (N.Y. Veh. & Traf. Law § 1192(1)-(3).)

So “what is a DUI” has a two-part answer in almost every statute read here: impaired by alcohol or drugs to the degree that state’s statute describes, or at or over the per se number, whichever the state can prove.

Which term your state uses

The table lists only states whose statute was opened and read for this page. The codes of Ohio, Michigan, Wisconsin, Indiana, Massachusetts, Missouri, New Jersey, North Carolina and Arkansas could not be opened from this host when it was revised, so they are left out rather than repeated from secondary sources.

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OWI, OUI, DUII and DUAC: the other names

Some states change the verb, some the noun. The offense underneath is recognisably the same one.

OWI — operating while intoxicated (Iowa)

Iowa’s section 321J.2 is headed “operating while under the influence of alcohol or a drug or while having an alcohol concentration of .08 or more (OWI)”. A person commits “operating while intoxicated” by operating a motor vehicle while under the influence of an alcoholic beverage or other drug, with an alcohol concentration of .08 or more, or with any amount of a controlled substance in the blood or urine. A first offense is a serious misdemeanor, a second an aggravated misdemeanor, and a third or later a class “D” felony (Iowa Code § 321J.2(1), (2).)

OUI — operating under the influence (Maine)

Maine’s section 2411 is headed “Criminal OUI”: a person commits OUI by operating a motor vehicle while under the influence of intoxicants, or with an alcohol level of 0.08 grams or more per 100 milliliters of blood or 210 liters of breath (29-A M.R.S. § 2411(1-A).)

DUII — driving under the influence of intoxicants (Oregon)

Oregon’s offense is “driving while under the influence of intoxicants”: driving with 0.08 percent or more, under the influence of an intoxicant or combination of intoxicants, or with 0.08 or more within two hours after driving without drinking in between (ORS 813.010(1).)

DUAC — driving with an unlawful alcohol concentration (South Carolina)

South Carolina keeps the number out of its DUI section and gives it a section of its own: it is unlawful to drive while the person’s alcohol concentration is eight one-hundredths of one percent or more, and the offense is “driving with an unlawful alcohol concentration” (S.C. Code § 56-5-2933(A).)

The verb is not decoration. Iowa and Maine say “operates”; Arizona and Florida add “actual physical control”; Washington has a separate physical-control offense; Minnesota covers driving, operating or being in physical control. What each of those reaches is a question of that state’s case law, which this page does not summarise.

The states where both exist as separate offenses

Four patterns account for the states read here that use two or more names.

Split by severity: Maryland

Maryland charges “under the influence” and “impaired by alcohol” as two offenses at two different levels of seriousness, and it is the state where the intuitive ordering is wrong. Details in the next section.

Split by age: Texas

In Texas, DWI under Penal Code § 49.04 is the general offense and applies to every driver, including drivers under 21. Separately, § 106.041 of the Alcoholic Beverage Code creates “driving or operating watercraft under the influence of alcohol by minor”, which applies only to minors and requires nothing more than any detectable amount of alcohol — no BAC figure, no proof of impaired faculties. It is a Class C misdemeanor — except that a minor who is not a child and has at least two prior convictions faces a fine of $500 to $2,000, up to 180 days in jail, or both — and a first conviction also brings 20 to 40 hours of community service related to alcohol education or prevention.

The statute is explicit that these are independent offenses rather than degrees of one: § 106.041(g) states that the minor’s offense is not a lesser included offense under Penal Code sections 49.04, 49.045, 49.06 or 49.061.

Split by degree of impairment: New York and Colorado

Neither state calls its lesser offense a DUI. Both call it DWAI, and they mean different things by it. That is the subject of the section after next.

Split by proof: South Carolina

South Carolina puts impairment and the number in two sections with two penalty clauses. A person who drives under the influence to the extent that faculties are materially and appreciably impaired is guilty of driving under the influence under S.C. Code § 56-5-2930(A); a person who drives with an alcohol concentration of 0.08 or more is guilty of the separate offense of driving with an unlawful alcohol concentration (§ 56-5-2933(A).)

Maryland, where the order is reversed

If you remember one thing from this page, make it this one. Maryland’s Transportation Article § 21-902 contains both offenses, and the “impaired” one is the lesser:

• § 21-902(a) — under the influence. The more serious offense: driving or attempting to drive while under the influence of alcohol, or under the influence of alcohol per se. A first offense carries up to one year or a fine up to $1,200, or both; a second, up to two years or $2,400.
• § 21-902(b) — impaired by alcohol. The less serious offense. A first offense carries up to two months or a fine up to $500, or both; a second, up to a year or $500.

Transporting a minor raises both: a first “under the influence” offense with a minor aboard carries up to two years or $2,000 (Md. Code, Transp. § 21-902(a)(2), (b)(2).) The point system follows the same order. Section 16-402 assigns 12 points to driving while under the influence of alcohol or under the influence per se, and 8 points to driving while impaired by alcohol.

DWAI means two different things

Driving while ability impaired appears in the New York and Colorado codes and is not the same offense in both.

New York's four tiers

New York is the clearest example of a state that stacks several impaired-driving offenses in one section. These four live in Vehicle and Traffic Law § 1192:

Section 1195 adds evidentiary effects on top: a reading of 0.05 or less is prima facie evidence that the driver was neither impaired nor intoxicated; above 0.05 but below 0.07 is prima facie evidence of not being intoxicated and is relevant, without prima facie effect, on impairment; and 0.07 up to 0.08 is prima facie evidence of not being intoxicated but is given prima facie effect on whether ability was impaired. That is a level of statutory nuance no acronym can carry.

What the acronym does not change

The 0.08 level, and Utah

Every state read for this page that writes a per se number into its offense uses 0.08 for adult drivers, whatever it calls the offense; Maryland’s section 21-902 uses the phrase “under the influence of alcohol per se” instead of a number, and commercial-vehicle limits are lower (Minnesota writes 0.04). Federal law gives states a reason to settle on 0.08. 23 U.S.C. § 163 authorized grants, with appropriations authorized through fiscal 2005, to states with a 0.08 per se law, and since fiscal 2012 it has the Secretary of Transportation withhold 6 percent of certain federal highway apportionments from a state that has not enacted or is not enforcing one (§ 163(e)(2).)

Utah went the other way. Its Highway Safety Office records that Utah became the first state to lower its per se limit from 0.08 to 0.05, under House Bill 155, signed in March 2017 and effective December 30, 2018 (Utah Code § 41-6a-502).

Crossing state lines

Some states write out-of-state convictions into their own statutes rather than following the other state’s label. South Carolina’s interlock section is one example: a resident convicted in another state of driving under the influence, and subject to an interlock there, is held to South Carolina’s requirement for the longer of the two periods (S.C. Code § 56-5-2941(C).) Whether a conviction from elsewhere counts as a prior for enhancement turns on your own state’s enhancement section, not on the acronym.

Immigration

Matter of Castillo-Perez, 27 I&N Dec. 664 (A.G. 2019), is about good moral character, not moral turpitude: it holds that evidence of two or more DUI convictions during the relevant period establishes a rebuttable presumption that a non-citizen lacks the good moral character required for cancellation of removal. Anyone with immigration exposure needs an immigration lawyer as well as a criminal defense lawyer, because the two analyses do not run on the same track.

Entering Canada

Canada’s Criminal Code now sets a maximum of ten years for impaired driving prosecuted by indictment, under s. 320.19(1)(a). Under the Immigration and Refugee Protection Act, a conviction outside Canada for an offense that would carry a maximum of at least ten years if committed in Canada makes a person inadmissible on grounds of “serious criminality” under s. 36(1)(b). Travellers with an impaired-driving record should read Canada’s own admissibility guidance before going.

Four things people get wrong

1. “DWI is always the worse one”

True in Texas, meaningless in most of the states read here, and backwards in Maryland. There is no national ordering because there is no national offense.

2. “A first offense is basically a ticket”

Mostly false, with exceptions worth stating precisely. New York makes a first-offense DWAI a traffic infraction under VTL § 1193(1)(a), but DWI there is a misdemeanor. Colorado makes driving under 21 at 0.02 to 0.05 a class A traffic infraction. Iowa makes a first OWI a serious misdemeanor, and Texas’s under-21 DUI is a Class C misdemeanor except on a third or later conviction of a minor who is not a child. The license is another matter: New York still suspends it for 90 days on a first DWAI under § 1193(2)(a)(1) — or revokes it for a year if the driver was under 21 or holds a commercial license, under § 1193(2)(b)(5) and (6) — and Iowa revokes it for 180 days to a year on a first OWI (§ 321J.2(3)(d).)

3. “Refusing the test means they have no evidence”

In Birchfield v. North Dakota, 579 U.S. 438 (2016), the Supreme Court held that the Fourth Amendment permits warrantless breath tests incident to arrests for drunk driving but not warrantless blood tests, and it upheld a Minnesota driver’s criminal prosecution for refusing a breath test. Motorists may not be criminally punished for refusing a blood test on the basis of implied consent, and the Court said nothing in its decision casts doubt on implied-consent laws that impose civil penalties. What refusal costs in each state is set out in what refusing actually trades.

4. “It comes off my record after a few years”

Two different clocks get confused here. One is how long a conviction stays visible on your driving record or criminal history. The other is the lookback period — how far back the state reaches when deciding whether this offense is your second or your third. They are separate rules, and the reliable move is to read your own state’s enhancement statute rather than a list. How long a DUI stays on your record sets the record clocks side by side.

Questions

What is the difference between a DUI and a DWI?

In most of the fifteen states read for this page, nothing but the word: the legislature named one offense, and DUI (driving under the influence) or DWI (driving while intoxicated, or in Minnesota’s statute driving while impaired) is what it chose. The difference becomes real only in states that use two names for two offenses. Maryland’s “under the influence” offense carries up to a year in jail, a fine up to $1,200, or both for a first conviction; its “impaired by alcohol” offense up to two months, a fine up to $500, or both. New York and Colorado pair DWI or DUI with a lesser DWAI, South Carolina pairs DUI with a separate 0.08 offense (DUAC), and Texas pairs DWI, which covers every driver, with a separate under-21 DUI.

What is a DUI?

Driving a vehicle while under the influence of alcohol or drugs, or with a blood or breath alcohol concentration at or above the per se level — 0.08 for adult non-commercial drivers in every state code read for this page that writes a number, while Utah, by its Highway Safety Office’s account, uses 0.05. Most statutes give both routes. California’s section 23152 makes it unlawful to drive under the influence of an alcoholic beverage, and separately with 0.08 percent or more. Florida’s section 316.193 requires normal faculties impaired, or 0.08 or more.

What does DWI mean?

Driving while intoxicated, in Texas and New York. Texas defines “intoxicated” in Penal Code section 49.01 as not having the normal use of mental or physical faculties by reason of alcohol or another substance, or having an alcohol concentration of 0.08 or more. Minnesota’s statute uses the same three letters for a different phrase: section 169A.20 is headed “driving while impaired”.

What does OWI mean?

Operating while intoxicated. Iowa’s section 321J.2 is headed “operating while under the influence of alcohol or a drug or while having an alcohol concentration of .08 or more (OWI)”, and a first offense is a serious misdemeanor. The verb is “operates” rather than “drives”; Maine’s OUI (operating under the influence) uses the same verb.

What is DWAI?

Driving while ability impaired, and it means two different things in the two states read here that use it. In New York, under Vehicle and Traffic Law section 1192(1), it is impairment by alcohol with no BAC figure in the offense, and section 1193 makes a first one a traffic infraction. In Colorado, under section 42-4-1301(1)(b), it is impairment to the slightest degree and it is a misdemeanor, and a reading above 0.05 but below 0.08 permits an inference of impairment.

Is a DWI worse than a DUI?

Only where a state has both, and then it depends on the state. Maryland’s order may surprise anyone who assumes DWI outranks DUI: the “under the influence” offense under Transportation Article section 21-902(a) is the more serious one, and the “impaired by alcohol” offense under 21-902(b) the lesser. In Texas, DWI is the general offense and DUI is a separate under-21 offense, a Class C misdemeanor except for a third or later conviction of a minor who is not a child.

Is a first DUI a crime everywhere?

Not quite, and the exceptions are specific. New York makes a first-offense DWAI a traffic infraction, though DWI itself is a misdemeanor there, and still suspends the license for 90 days (a year for a driver under 21 or a commercial license holder). Colorado makes driving under 21 at 0.02 to 0.05 a class A traffic infraction. Iowa makes a first OWI a serious misdemeanor and revokes the license for 180 days to a year.

Can I refuse the breath test and avoid the whole thing?

No. In Birchfield v. North Dakota (2016) the Supreme Court held that the Fourth Amendment permits a warrantless breath test incident to an arrest for drunk driving, and it upheld a Minnesota driver’s criminal prosecution for refusing one. A blood test is different: it cannot be taken without a warrant as a search incident to arrest, though the Court noted police may seek a warrant or rely on the exigent-circumstances exception where it applies, and a motorist cannot be criminally punished for refusing a blood test on the basis of implied consent. The Court said nothing in its decision casts doubt on implied-consent laws that impose civil penalties.