Why there is no average car insurance cost

What a national average would have to be built from

Every published figure for the average cost of car insurance has to come from somewhere, and there are only three places it can come from: a regulator, an industry aggregation, or a rating engine run against invented driver profiles. Almost every figure in the search results comes from the third, which is why they contradict each other and why none shows its working.

The regulator route is the only one with a public document behind it, and it reaches 13 of 51 jurisdictions. The remaining 38 publish no comparable premium data at all. A national average is therefore an estimate stitched across a hole covering most of the map.

The 13 that do publish are not measuring the same thing. Exactly 6 of them publish six-month premiums (Arizona, District of Columbia, North Dakota, Nevada, Oklahoma and Utah) and 7 publish annual premiums (California, Florida, Hawaii, Maryland, New Hampshire, Texas and West Virginia). Doubling one to match the other is not a conversion: a six-month policy is priced as a six-month policy, not as half of an annual one.

The dates do not line up either. The oldest survey in this site’s committed data is Arizona’s, with rates effective March 2023; the newest is Maryland’s, effective August 2026. A further 3 regulators publish no effective date anywhere in their document (Florida, Nevada and Utah), so their figures cannot honestly be placed on a timeline beside the rest.

Thirteen vocabularies that do not translate

A premium figure means nothing without the driver it describes, and each regulator invents its own set of hypothetical drivers. The sets do not overlap.

The California Department of Insurance rates a factorial grid of 292 profiles built from age band, marital status, credit tier, driving record and liability limit. Another state publishes a short list of hand-written narrative scenarios, each naming a vehicle and fixing the comprehensive and collision deductibles. A third has no gender dimension at all, because state regulation bans gender as a rating factor. A fourth splits every example by credit standing.

These are not variants of one profile. They are different questions. No arithmetic turns a full-coverage narrative scenario with fixed deductibles in one state into a liability-only factorial cell in another, and a national average has silently performed exactly that conversion on the way to its headline.

This site therefore keeps every state in its own page family and never places two states’ premium figures in one table. That rule is enforced by a build gate rather than by editorial discipline, because the temptation to build the comparison table is permanent.

The caution printed on the one national aggregate

One genuinely national dataset of auto premiums does exist, compiled by the association of state insurance commissioners. Its own front matter explains what it does and does not support:

“Aggregate written premiums and aggregate written exposures are used in calculations with no distinction as to policyholder classifications, vehicle characteristics, or the selection of specific limits or deductibles… CAUTION: Because of these differences, direct comparisons between state results should be treated with a high degree of caution.”

Read that against the pages ranking for average car insurance cost by state. The comparison the document warns against is the entire premise of those pages. The warning is not buried; it is printed in the front of the publication they lean on.

One number describes almost nobody

Even inside a single state, a single geography and a single regulator-defined profile, filed rates spread far more widely than any average suggests. The evidence comes from the regulators’ own tables.

In San Francisco - Glen Park, California, the California Department of Insurance publishes 48 filed annual rates for one defined profile out of the 292 it rates. The lowest is $5,258 and the highest is $220,416. A quarter of the filed rates sit at or below $9,697, a quarter at or above $19,347, and the median is $12,512. A driver told that the average is $12,512 has learned something true about the middle of that list and nothing whatever about its width.

The widest single cell anywhere in this site’s committed data is in San Francisco - Glen Park, California. Against one profile published by the CDI, 48 filed annual rates run from $5,258 to $220,416, so the highest is 41.9× the lowest for the same driver, the same vehicle use and the same coverage.

Geography moves the answer as hard as the driver does. For a single published profile in Nevada, the median in North Las Vegas runs 199.3% above the median in Fallon, $5,044 against $1,685. Inside a single California rating territory, the highest published profile median is 28.1× the lowest, $20,549 against $732.

What this site publishes instead

Where a regulator publishes filed rates, this site publishes the distribution: the number of filed rates behind the cell, the minimum, the twenty-fifth percentile, the median, the seventy-fifth percentile and the maximum. Every figure carries the regulator that published it, that regulator’s own definition of the driver, the policy term, the effective date and the sample size. Nothing is attributed to an insurer and nothing is ranked.

Sample size travels with every figure because it is not constant. The largest sample behind any single published cell is 102 filed rates, in Arizona; the smallest is 14, in North Dakota, where most insurers decline to rate the riskier hypotheticals at all. A distribution built from 14 filings is a weaker claim than one built from 102, and the page says so.

Where no regulator publishes anything, this site publishes no premium figure. That covers 38 jurisdictions. Those pages carry statutory requirements, tort status and rating rules instead, all of which are exactly answerable from law. Declining to invent a number there is why the numbers elsewhere can be relied on.

Questions

Is there a national average car insurance cost?

No figure of that kind can be traced to a document. 13 of 51 jurisdictions have a regulator-published premium survey and 38 have none, and the ones that publish use different driver definitions, different policy terms and different effective dates.

Why not simply average the states that do publish?

Because 6 of them publish six-month premiums and 7 publish annual premiums, their hypothetical drivers are not the same driver, and 3 publish no effective date at all. The result would be an average of different questions.

What does the published data support instead?

A distribution for a profile a regulator actually published, in a geography that regulator actually reported, with its sample size, policy term and effective date attached. Where no such publication exists, the statutory requirements and the national price index are the sourced answers available.