One way auto insurance companies compete for your business is by offering an array of discounts.

With the wide range of discounts available, chances are you’re eligible for at least a discount or two. But how much can you really save? decided to find out. In an extensive study, they gathered price breaks for 49 discounts in every state among large car insurance companies. In all, they looked at 24,988 potential discounts nationwide. They were able to determine the most common discounts, the biggest savers, and the states where you’re most likely to find discounts...

While you might expect car insurers to offer the same discounts in every state, they don’t.

Missouri and Connecticut came out on top, with savings available 33 percent of the time across the range of 49 discounts surveyed. But many states were very close – see the list at right.

Hawaii and North Carolina have the lowest availability among the discounts we surveyed, at 14 percent and 13 percent, respectively.

A few discounts stand out as often being big money-savers. Discounts based on being a good student, marital status and low annual mileage ranked highest for average percent off, when offered. But discounts vary considerably; we observed discounts much higher (some topping 25 percent) and some much lower than the averages shown below.

Average discount savings (nationwide)

Good Student - 16%
Marital Status - 14%
Annual Mileage - 11%
Use of Car - 10%
Concurrent Home Policy - 9%
Payment Type - 9%
Days Advanced Purchase - 8%
Driver Training - 7%
Residence Type/Occupancy - 6%
Persistency/Renewal Months - 6%
Concurrent Life Policy - 4%
Electronic Funds Transfer - 4%
Attained Degree - 4%
Vehicle Ownership - 4%
One-Way Commute - 4%
Days Per Week Driven - 4%
We also looked at which discounts are the most commonly available. Good student discounts and buying a homeowners, renters or condo insurance policy from the same company are the most likely to yield savings.

The most common discounts & percent of time offered:

Good Student - 77%
Concurrent Home Policy - 68%
Payment Type - 46%
Marital Status - 41%
Driver Training - 41%
Use of Car - 40%
Concurrent Life Policy - 37%
Persistency/Renewal Months - 36%
Electronic Funds Transfer - 34%
Days Advanced Purchase - 26%
One-Way Commute - 22%
Residence Type/Occupancy - 21%
Annual Mileage - 13%
Days Per Week Driven - 8%
Vehicle Ownership- 7%
Attained Degree - 6%

If you want to save money, they advise consumers to keep in mind these common wrinkles:

Some insurers cap your discount, so while you may be “eligible” for more savings, you won’t get it all.
Discounts may apply only to a portion of your car insurance bill, not to your total premium.
Insurers have different eligibility rules for discounts. For example, check with your insurer on its definition of a “good student” before you count on savings. And a good student discount is often available only to drivers under age 25.

Use's Discount Detector to identify maximum savings.