What is the minimum jail time for a first DUI?

In Montana, the minimum jail time for a first offense is 24 hours and the maximum is 6 months [§ 61-8-1002]. Actual time served depends on the facts and circumstances.

How much does a DUI cost in total?

The statutory fine range for a first offense is $600 to $1,000 [§ 61-8-1002], but the total cost is substantially higher when you include surcharges, court costs, substance abuse programs, IID installation and monitoring fees, increased insurance premiums, and attorney fees.

How far back do prior offenses count?

Montana uses a 10 years [def:lookback period] for determining how prior offenses affect sentencing [§ 61-8-1002].

Topic guideUpdated 2026-02-27

Montana DUI Penalties — Fines, Jail & Probation

Common consequences to discuss with counsel.

DUI penalties in Montana escalate significantly with each subsequent offense and with aggravating factors like high BAC §61-8-1002. Understanding the penalty structure helps you assess the stakes and make informed decisions.

First offense §61-8-1002

A first DUI in Montana is classified as a misdemeanor.

Jail: 24 hours minimum to 6 months maximum
Fine: $600 to $1,000
License suspension: 6 months
Substance abuse program: chemical dependency education course and evaluation required
Community service: 24 hours community service may substitute for minimum jail
Probation: available

Second offense

Jail: 7 days minimum to 6 months maximum
Fine: $1,200 to $2,000
License suspension: 1 year

Third and subsequent offenses

Jail/prison: 30 days minimum to 1 year maximum
Fine: $2,500 to $5,000
License suspension: 1 year
Felony threshold: fourth offense (or third within 5 years) is a felony with up to 13 months in state prison

Penalty comparison by offense tier

	Offense	Jail Range	Fine Range
First DUI	24 hours–6 months §61-8-1002	$600–$1,000 §61-8-1002	6 months §61-8-1002
Second DUI	7 days–6 months §61-8-1002	$1,200–$2,000 §61-8-1002	1 year §61-8-1002
Third DUI	30 days–1 year §61-8-1002	$2,500–$5,000 §61-8-1002	1 year §61-8-1002

Lookback period

Montana uses a 10 years Lookback period to determine how prior offenses affect sentencing. Only DUI convictions within this window count toward the escalating penalty tiers.

Enhanced penalties for aggravating factors

Substantially elevated BAC above the standard limit (aggravated DUI — stiffer penalties; confirm the exact threshold with a lawyer)
Prior DUI within 10 years
Child under 16 in vehicle
Serious bodily injury or death (separate felony charges)

What these penalties mean in practice

Mandatory minimums cannot be suspended or reduced by the judge — they must be served. Fines do not include surcharges, court costs, and program fees, which can substantially increase the total financial impact. License suspension affects employment, insurance rates, and daily logistics.

⚠Penalty ranges are statutory minimums and maximums. The actual sentence depends on the facts, the judge, local practice, and the quality of the defense. An experienced DUI attorney can often identify mitigating factors or procedural issues that affect the outcome.

Prepare for Your Consultation

Quick checklist (DUI)

Dates matter. If you have paperwork, bring it.

Citation or arrest

paperwork

Court dates

or hearing notices

Your timeline of events

(brief)

General preparation tips only. Deadlines vary by facts and jurisdiction.

No Obligation

Ready to Talk to a Lawyer?

Submit a short intake form and a participating Montana attorney who handles this type of matter may reach out to you. No commitment required.

Request a Free Consultation →

No attorney-client relationship is created unless you later sign an engagement agreement. Participating attorneys may pay a marketing fee to receive inquiries.

Common Questions