How Insurers Calculate Your Premium — And How to Lower It

Rating factors are the variables used to make that estimate. Some are obviously relevant, some are statistically predictive without being intuitive, and a few are contentious enough to be restricted or banned in particular states.

Where you live does most of the work

Location is typically the single largest input in both auto and property insurance, and it operates at a granular level — often by ZIP code or finer.

For auto, it reflects local claim frequency, traffic density, theft and vandalism rates, the cost of repair labour nearby, and how litigious the jurisdiction is. Two identical drivers a few miles apart can pay materially different premiums for reasons that have nothing to do with either of them. For property, it reflects weather exposure, distance to a fire hydrant and a fire station, and local construction costs.

Credit-based insurance scores

In most US states, insurers use a credit-based insurance score as a rating factor, because it correlates with claim frequency. It is not your lending credit score, though it draws on the same data.

The effect is often larger than people expect — in some states, comparable to a moving violation. California, Hawaii, Massachusetts and Michigan restrict or prohibit its use in auto insurance, and Maryland restricts it in homeowners. Everywhere else, improving your credit lowers your insurance cost even though no one will send you a letter telling you so.

Claims history, including claims you did not make

Your own claims history matters, and so does something less obvious: enquiries. In many cases, calling to ask about a potential claim is logged in the industry-wide loss database even if you never file. Two or three of those can affect your rating.

The practical implication is to ask hypothetically and without identifying details when exploring whether something is worth claiming, and to think carefully before filing anything close to your deductible. A $900 claim on a $500 deductible nets you $400 and may cost you considerably more across three years of surcharged renewals.

The factors you can actually move

Coverage structure is the most direct lever. Raising deductibles reduces premium immediately. Dropping collision and comprehensive on a low-value vehicle removes cover that could not pay you much anyway.

Bundling is usually the largest single discount available, commonly 10 to 20 percent across policies. Paying annually rather than monthly avoids instalment fees that often work out to a meaningful effective interest rate. Telematics can help materially if your driving is genuinely moderate — and can hurt if it is not, so it suits low-mileage, uneventful drivers.

Then there is accuracy. Annual mileage brackets, garaging address, whether the car is used for commuting, who actually drives it: all of these are frequently out of date on long-held policies, and all of them affect price. A household that stopped commuting in 2020 and never updated the policy may have been overpaying for years.

Property-specific levers

For homeowners, mitigation features attract real discounts: monitored alarms, water leak detection with automatic shutoff, impact-resistant roofing in hail regions, wind mitigation features in hurricane zones. Some of these pay for themselves in a few years of reduced premium.

Roof age is now a dominant factor in weather-exposed states, and some insurers will not write new business on roofs over a certain age at all. If you are replacing a roof anyway, the insurance implications of the material choice are worth asking about first.

Shop deliberately, on a schedule

The largest single saving available to most households is not a discount, it is changing carrier. Insurers routinely price new business more competitively than renewals, and the same risk profile can produce quotes 30 to 50 percent apart.