How Much Car Insurance Do I Need?

What this page tells you, and what it does not

This page answers a different question from the site's car insurance cost estimator. That tool starts from the average premium and prices the bill from your age, record and state. This page starts from your money and tells you how much coverage to buy: the liability limits, the deductible, and whether collision and non-collision coverage still make sense on your car. Both belong together, but the cost estimator never tells you the minimum is too thin, and this page never tells you the final price.

The countrywide average auto expenditure was $1,281 per vehicle in 2023, the latest NAIC data year, and the combined average premium for a policy carrying all three coverages was $1,438 (per the NAIC 2022 to 2023 Auto Insurance Database, published 2025). A 2026 AAA study put the average full coverage premium for the vehicles it priced at $2,098. Use those as anchors, then read on to size the limits to your own situation.

Coverage is written as three numbers, for example 100/300/100. The first is the most the insurer pays for bodily injury to one person, the second is the most it pays for all injuries in one crash, and the third is the most it pays for property you damage. Everything below is about picking those three numbers and the deductible on the physical damage part.

Know your state's legal minimum, then plan to clear it

Every state except New Hampshire sets a legal minimum, and the minimum is the floor, not a recommendation. Below are representative minimums, with the official state page linked where one was checked.

Minimums change. The III compilation used here dates from 2024, and California raised its limits on January 1, 2025, so confirm the current figure with your state insurance department before you buy a policy.

The gap shows up the moment a real claim lands. The Insurance Information Institute reports the average 2024 bodily injury liability claim was $28,278, and the average property damage claim was $6,770. A driver carrying a $25,000 per person limit who causes a $28,278 injury is on the hook for the rest.

Worked example: a $25,000 per person limit against a $28,278 average bodily injury claim leaves 28,278 minus 25,000 = 3,278 dollars of exposure. The NAIC consumer shopping guide puts it plainly: if you cannot afford to pay the amount above your limit, you should buy more than the minimum. The minimum is legal, but it is not a plan.

Size your liability limits to what you could lose

Liability limits exist to protect the assets a lawsuit could reach: your savings, your home equity, and a portion of your future wages. A clean rule of thumb is to set limits at or above the dollars you would not want to lose in a judgment.

Worked example: a renter with 60,000 dollars in savings and investments sits in the middle band, so the tool recommends 100/300/100. Against a state minimum of 25,000 dollars per person, that is a coverage gap of 100,000 minus 25,000 = 75,000 dollars filled. If you own a home or have a six figure income, step up to 250/500/250 and price a million dollar umbrella, which usually costs far less than raising auto limits that high on the auto policy alone.

These bands are a starting point, not legal advice. A few states require higher limits than the floor, and lenders always require full coverage on a financed car regardless of your assets.

What the step up in limits costs

The premium model below is anchored to the 2026 AAA average full coverage premium of $2,098 for a 100/300/100 policy with a $500 deductible driven 15,000 miles. It then applies transparent multipliers. The exact coefficients vary by insurer and state, so treat the output as an estimate, not a quote.

Premium = 2,098 x age factor x record factor x mileage factor x (0.55 x limit factor + 0.45 x deductible factor)

The 0.55 and 0.45 split reflects that liability is roughly half of a full coverage bill, and the deductible only moves the physical damage half. At the clean, 25 to 64, 15,000 mile, $500 deductible default the formula returns exactly 2,098 dollars a year, or 174.83 dollars a month.

Worked example: moving from 100/300/100 to 250/500/250 at the same profile adds the limit factor 1.14, so the premium becomes 2,098 x (0.55 x 1.14 + 0.45) = 2,259.55 dollars, about 161.55 dollars a year, or 13.46 dollars a month. For a 20 to 24 year old with a clean record, the same 100/300/100 policy is 2,098 x 1.65 = 3,461.70 dollars a year, which is why young drivers feel the limit step up less than the age step.

How your record and mileage move the premium

Two levers outside the limits themselves move the bill as much as the coverage does: your record and your mileage. The record factors in the model follow the pattern insurers publish and the III describes: one minor ticket raises the premium 25 percent, one at fault accident 45 percent, and a DUI nearly doubles it. Annual mileage matters too, and the model moves the premium 20 percent for each 15,000 mile swing from the 15,000 mile baseline, clamped between 0.85 and 1.30.

Worked example: a 20 to 24 year old with one ticket, driving 30,000 miles, on a 25/50/25 policy with a $500 deductible. The factors multiply to 1.65 x 1.25 x 1.20 = 2.475 on the age, record and mileage side, and the coverage side is 0.55 x 0.82 + 0.45 = 0.901, so the premium is 2,098 x 2.475 x 0.901 = 4,678.49 dollars a year. That is more than double the clean, 25 to 64 baseline, which is why the record matters more than the limit choice for risky profiles.

Worked example at the other end: a low mileage driver at 5,000 miles a year gets a mileage factor of 0.87, so the same default policy drops to 2,098 x 0.87 = about 1,818 dollars a year. Telematics programs can formalize that discount if your driving data supports it.

Pick a deductible you could pay on claim day

The deductible is the amount you pay on a collision or non-collision claim before the insurer pays. The Insurance Information Institute notes that raising a deductible from $200 to $500 can cut the physical damage portion of the premium 15 to 30 percent, and moving to $1,000 can save 40 percent or more, but only if you could produce that cash after a crash.

Worked example on the $2,098 baseline: a $500 deductible carries an implied physical damage factor of 1.00, while a $1,000 deductible uses 0.78. The annual premium at $1,000 is 2,098 x (0.55 + 0.45 x 0.78) = 1,890.30 dollars, a saving of 207.70 dollars a year versus the $500 deductible. The extra $500 you would pay at claim time breaks even in 500 divided by 207.70 = 2.41 years. If you change cars or insurers before then, the higher deductible costs you more than it saves.

Pick the highest deductible whose lump sum you could cover from savings on the day of a claim. A deductible you cannot pay turns a covered loss into an uncovered one.

The factors in the table are the same ones the calculator above uses, so the premium column matches the tool output for the default profile.

Collision and non-collision: when the math says drop them

Collision and non-collision coverage pay for your own car, with collision covering crashes and non-collision covering theft, hail, flooding and animal strikes. A common rule is to drop them once the annual physical damage premium exceeds about 10 percent of the car's value, because you are then paying more than the car is worth to protect it.

Worked example: the physical damage share of the $2,098 baseline is 2,098 x 0.45 = 944.10 dollars a year. On a car worth 4,000 dollars, 10 percent is 400 dollars, so the 944 dollar premium is 944.10 divided by 4,000 = 23.6 percent of the car's value. That is well past the 10 percent line, so dropping collision and non-collision coverage makes sense on that car. On a 20,000 dollar car the same 944 dollars is under 5 percent, so keeping the coverage is the better call.

Two exceptions. A lender or lessor requires full coverage no matter the math, and if you could not replace the car without the payout, the premium is the price of that safety net.

Uninsured motorists and why 100/300/100 is a floor

Even perfect limits do not help if the other driver has no insurance. The Insurance Research Council's 2025 study, reported by the Insurance Information Institute, found 15.4 percent of US motorists, more than one in seven, were uninsured in 2023.

That is the case for matching your uninsured and underinsured motorist coverage to your liability limits, so a hit and run or an uninsured at fault driver draws on the same 100/300/100 or 250/500/250 bucket. Several states already require uninsured motorist coverage, and a few fold it into the minimum.

The practical answer to how much car insurance you need is therefore three numbers plus a deductible: liability limits sized to your assets, an equal uninsured motorist limit, a deductible you could pay, and collision and non-collision coverage only while the math favors them. Run the calculator above with your own savings, state minimum and car value to turn those rules into dollar figures.