If you sit around and discuss auto insurance premiums with a handful of your friends, chances are you’ll learn that all of you are paying a different price — even if you have the same insurer and identical policies. While that may seem unfair, the price you pay for auto insurance comes down to personal data about you.

The price you pay for auto insurance has everything to do with how risky auto insurers believe you are to insure, says John David, author of Ten Questions: The Insider’s Guide to Saving Money on Auto Insurance. If an auto insurer thinks you’re very likely to have an accident or file a claim, it’s going to charge you a higher rate than if that insurer believes you’re a safe driver who isn’t going to file a claim.

While auto insurers don’t know for sure who will ultimately file a claim, they make educated guesses based on research that shows that certain groups of people are more likely to file an insurance claim than others.

Most insurance companies remain mum on the exact formulas they use to set their rates and which factors carry the most weight. But here are some personal details about you that are likely to impact your auto insurance bill.

Your age. Everyone wants to be young – except when it comes to paying for car insurance. According to the Insurance Institute for Highway Safety, teenagers between the ages of 16 and 19 are about three times more likely to crash than drivers 20 and older who drive the same number of miles. As a result, insurance policies that cover teens typically will have a higher rate than policies that don’t.

Drivers over the age of 75 also are likely to be charged higher rates since they are more likely to have accidents than the general population, according to the Idaho Department of Insurance.

If you’re wondering at what age your rates are likely to go down, 25 is often the magic number – with all other factors being equal.

Your gender. While equality between the sexes is a great notion, it doesn’t apply to auto insurance rates. Studies show that male drivers are more likely to be in accidents than women. As a result, some insurance companies charge higher rates to men, particularly those under the age of 30 since that group is particularly prone to accidents.

Your credit score. According to the Property Casualty Insurers Association of America, studies show that people who have higher credit scores file fewer claims. Not surprisingly, many insurance companies factor your credit score into your rate. If you have a lower credit score, you may pay more for insurance than someone who has better credit. However, a few states outlaw this practice. In California, Massachusetts and Hawaii, it’s against the law for insurers to consider credit scores when determining the rate for auto insurance.

Your neighborhood. When it comes to paying for auto insurance, zip code does matter. If you live in a city with plenty of car thefts, for example, your auto insurance is likely to be higher than it would be if you lived in a neighborhood that rarely experiences crime.

Your car. The vehicle you drive isn’t just a status symbol; it’s also a major determinant in how much you pay for auto insurance. Expensive cars tend to have more expensive parts so they’d be more expensive to repair. As a result, insurance companies often charge higher rates to drivers of luxury models. The safety factor also is important. Drivers of models that are involved in a lot of crashes are typically charged higher rates than drivers of models that are deemed safer. If you’re wondering how safe your car is, the Insurance Institute for Highway Safety publishes a list of the safest vehicles each year.