Montana DUI Laws & Penalties (2026)
Montana has a 10-year lookback for DUI penalties but uses a lifetime lookback for felony charges (4th offense ever).
Montana DUI Penalties
1st Offense
2nd Offense
BAC Limits in Montana
💰 Estimated Total Cost
A first DUI in Montana typically costs $10,000-$25,000+ including fines, attorney, classes, IID, and insurance increases.
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Montana DUI Deep Dives
🚨 First Offense Penalties
Complete guide to what happens on your first DUI in Montana.
🍺 BAC Limit
Legal BAC limits for standard, commercial, and under-21 drivers.
💰 DUI Cost
Full cost breakdown: fines, attorney, classes, insurance, and more.
🔧 Ignition Interlock Cost
IID installation, monthly fees, and provider comparison.
🚫 License Suspension
Suspension length, restricted license options, and reinstatement steps.
🧮 Cost Calculator
Estimate your total DUI cost with our interactive tool.
Official Sources & References
- 📋 Mont. Code § 61-8-401 — Montana DUI statute
- 🚗 Montana DMV — License suspension, reinstatement, IID requirements
- 📊 NHTSA Impaired Driving Data
- 🛡️ MADD — Mothers Against Drunk Driving
DUIFinders.com is not a law firm and does not provide legal advice. Information is for general purposes only. Consult a licensed attorney in Montana for advice specific to your situation.
Montana DUI FAQ
What is the BAC limit in Montana?
The legal BAC limit in Montana is 0.08% for regular drivers, 0.04% for commercial drivers, and 0.02% for drivers under 21.
What are the penalties for a first DUI in Montana?
A first DUI in Montana is a Misdemeanor. Penalties include Up to 6 months (24 hours mandatory) jail, $600–$1,000 in fines, and 6-month suspension license suspension.
Is an ignition interlock device required in Montana?
Required for repeat offenders
Can a DUI be expunged in Montana?
No, Montana does not allow DUI expungement.
What is the lookback period for DUI in Montana?
Montana uses a 10-year lookback period to determine if an offense counts as a repeat offense.