Paying too much for auto insurance? Your credit score could be the culprit. A bad credit score hikes insurance premiums by an average of 65 percent, according to a new study by WalletHub.

However, the exact impact varies dramatically by insurer and the state where you live, according to the study. Your credit score is most important when insuring with Allstate, and least impactful when you insure with State Farm, according to the study.

State laws also affect whether your credit score can be used against you. In California, for example, state law dictates what factors can be used to set auto insurance rates and credit scores are not among them. Thus, California is one of just a few states where your credit score has no impact on your auto insurance rates.

But if you're buying an auto insurance policy in Maine, Michigan, Wyoming, Indiana or the District of Columbia, you can expect a bad credit score to double what you pay, according to the study. And states where credit scores account for an increase of more than 50 percent far outnumber the regions where credit scores have little or no impact. There were only three states where credit score didn't matter at all -- California, Massachusetts and Hawaii. On the other hand, in Washington, D.C., the premium for the consumer with no credit was 126 percent higher than for the consumer with great credit. In Wyoming, credit accounted for a 114 percent premium swing; in Indiana it accounted for a 110 percent difference in rates; in Maine the difference amounted to 109 percent; and in Michigan it hiked rates by 100 percent. To check the impact in your state, go to WalletHub's map here.

To conduct the research, WalletHub got auto insurance quotes from five of the nation's largest auto insurers for two hypothetical consumers who were identical in every way except one. One of these two 36-year-old males had great credit; the other had no credit. That allowed the site to isolate the impact of credit on insurance rates on a state-by-state and company-by-company basis.

The impact of credit scores also varied dramatically from insurer to insurer. With Allstate, credit scores matter a lot, accounting for an average premium difference of 116 percent, according to the study. They matter less with State Farm, where the average difference in premium was 45 percent.

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