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How our estimates work

Our calculator is a model, not a quote engine. Here is exactly what goes into it, where the numbers come from, and where it can be wrong.

Data and rules last checked November 2026.

1. State price anchors

For every state we start from two published averages for a standard adult driver: a full-coverage policy (100/300/100 liability with comprehensive and collision) and a policy with only the state's legal minimum coverage. Publishers survey different drivers and cars, so we combine several recent sources rather than trusting one. Each state's position is the median, across six or seven sources, of that state's average divided by the source's national figure. That cancels out the different driver profiles each publisher uses. The dollar level comes from one national baseline of about $2,600 a year for full coverage and $800 for state-minimum coverage, reconciled from the same sources after adjusting for their deductibles, discounts and driver ages.

Car insurance prices rose about 58% from 2021 to 2025 (Bureau of Labor Statistics consumer price index for motor vehicle insurance, annual average 565.3 in 2021 vs. 893.5 in 2025), then eased: the September 2026 index was 5.0% lower than a year earlier.

2. Splitting the premium

A full-coverage premium is part liability (what you owe others) and part physical damage (your own car). We estimate the liability part at 100/300/100 from the state-minimum price using increased-limit factors, the multipliers insurers use to price higher limits, and keep it between 35% and 70% of the total. The rest is comprehensive and collision, split roughly 30% and 70%.

Published full-coverage averages already include uninsured motorist coverage in most states, so the calculator shows it as its own line (on by default, about 15% of the liability cost) and turning it off lowers the estimate. A state-minimum policy leaves it out unless your state requires it.

3. Your coverage choices

Higher liability limits cost more, but much less than proportionally: going from a typical state minimum to 100/300/100 usually adds far less than quadrupling the limits would suggest. Deductibles reprice only comprehensive and collision. Relative to $500, our collision multipliers are $250: +16%, $1,000: -16%, $2,000: -34%; comprehensive $250: +19%, $1,000: -20%, $2,000: -40%.

4. Driver, car and place

Each factor multiplies the baseline. Typical values we use:

FactorMultiplier vs. baseline
Age (own policy)16: 4.00x, 18: 2.89x, 20: 2.00x, 25: 1.18x, 30: 1.05x, 35: 1.00x, 50: 0.93x, 65: 0.91x, 75: 1.06x, 85: 1.24x
Driving record1 speeding ticket: +28%, 1 at-fault accident: +50%, Ticket + accident: +85%, 2 at-fault accidents: +117%, DUI / DWI: +88%
Credit (where allowed)Excellent credit: -14%, Good credit: baseline, Fair credit: +18%, Poor credit: +87%
Where the car is parkedCity: +22%, Suburb: baseline, Rural / small town: -15%
Type of car (car damage part)Compact / economy car: -8%, Mid-size sedan: baseline, SUV / crossover: -10%, Pickup truck: baseline, Minivan: -10%, Sports car: +50%, Luxury car: +50%, Electric vehicle: +30%

Factors a state bans are switched off. Credit-based pricing is not allowed in car insurance in California, Hawaii and Massachusetts; pricing by gender is not allowed in California, Hawaii, Massachusetts, Michigan, North Carolina and Pennsylvania. California also bars a higher price just for having had no prior insurance. Hawaii does not allow pricing by age or driving experience at all. California, Massachusetts and North Carolina price newer drivers by years licensed rather than age, so there the age curve only stands in for inexperience under 25 (Massachusetts also gives clean-record drivers 65 and older a 25% lower rate), and Rhode Island bars charging clean-record drivers 65 and older more for age. Every state page lists its own rules with links to the official sources.

5. Discounts

We apply typical discount sizes (bundle home or renters about 10%, more than one car about 12%, pay in full about 9%, autopay + paperless about 6%, safe-driving app about 10%, good student (under 25) about 11%, defensive-driving course about 10%) and cap the combined discount at 40%, because stacked discounts rarely add up in full.

6. Very high and very low results

Surcharges multiply, so a young driver with a DUI, poor credit and a sports car can stack up fast. Past about 5 times the standard price, drivers usually end up with nonstandard (high-risk) insurers whose prices the published averages do not describe, so we cap the stack there and flag the estimate. At the other end, no estimate drops below 45% of the state's minimum-coverage price or $240 a year, because insurers do not sell policies for pennies.

7. Why a range

The same driver can get very different prices from different companies, and insurers use details we never ask for. We show a range of plus or minus about 14%, wider for young drivers, serious violations, poor credit and expensive cars, where companies disagree the most.

What the model does not know

  • Your exact address. Prices can differ a lot between ZIP codes in the same state; the city, suburb and rural choice is a rough stand-in.
  • Your claims history, motor vehicle report and insurance score as each insurer calculates them.
  • Your car's exact make, model, trim and safety features.
  • Each company's filed rates, underwriting rules and which discounts it offers in your state.

Use the estimate to set expectations and to compare quotes like for like. A real price comes only from an insurer or a licensed agent. How we make money.

Sources for the multipliers