Updated July 2026
What Is Liability Insurance Insurance?
Liability insurance is the foundation of every Montana auto policy. It splits into two parts: bodily injury liability, which pays medical expenses and lost income for people you injure, and property damage liability, which pays to repair or replace vehicles and property you damage. When you cause an accident, your liability coverage pays the other party's bills up to your policy limits. Once your limits are exhausted, you pay the rest out of pocket.
- You're texting at a red light in Billings and rear-end the car ahead at 15 mph. The other driver has $8,000 in medical bills for a neck strain and their sedan needs $6,500 in repairs. Your 25/50/20 liability policy pays the full $14,500 because it falls under your per-person injury limit and property damage limit. Your own vehicle damage and any injuries you sustained are not covered.
- You lose control on black ice on I-90 near Missoula and slide into two vehicles. Driver one has $40,000 in medical expenses and driver two has $30,000. Your $50,000 per-accident bodily injury limit pays out in full, but the remaining $20,000 in medical bills becomes your personal debt. Property damage to both vehicles totals $18,000, which your $20,000 property limit covers, but you're still liable for the injury shortfall.
- You swerve to avoid a deer outside Bozeman and crash through a rancher's fence, causing $12,000 in damage to the fence and irrigation equipment. Your property damage liability pays the $12,000 claim. Your truck's $9,000 in damage is not covered because liability only pays for property you damage that belongs to others. You need collision coverage to repair your own vehicle.
Who Needs Liability Insurance Insurance?
Liability insurance is legally required for every Montana driver, but state minimums are rarely enough. If you own a home, have retirement savings, or earn a steady income, carry at least 100/300/100 limits. A single serious injury claim can exceed $50,000 in medical bills within days, and Montana law allows injured parties to sue you personally for the difference between your policy limit and their actual damages.
Start with Montana's 25/50/20 minimum, then calculate your financial exposure. Add up your home equity, savings, and annual income. If that total exceeds $50,000, increase your bodily injury limit to 100/300 or higher. If you cause an accident that injures multiple people, your liability limit is the only barrier between their medical bills and your personal assets.
How Much Does Liability Insurance Insurance Cost?
Montana liability-only policies typically cost $45 to $85 per month, or $540 to $1,020 annually, for state minimum 25/50/20 limits. Increasing to 100/300/100 limits adds $15 to $35 per month.
- Your at-fault accident history in the past three years — one at-fault crash can raise liability premiums 30 to 50 percent.
- Your home ZIP code and county — Yellowstone County drivers pay more than drivers in rural counties due to higher accident frequency.
- The liability limits you select — doubling your bodily injury limit from 25/50 to 50/100 typically adds $10 to $20 per month.
- Your age and driving experience — drivers under 25 and over 70 pay higher liability rates due to statistically higher claim frequency.
- Your credit-based insurance score in Montana — insurers use credit history to price liability coverage, and poor credit can double your premium.