How much does it cost to add a teenager to your car insurance?
It varies enormously by state. A CarInsurance.com analysis of Quadrant Information Services data found increases ranging from about 4% in Hawaii to roughly 137% in Maine, with Louisiana adding the most in dollars. Your state, carrier, vehicle assignment, and captured discounts determine where in that range your family lands.
The national headline number hides how wide the spread is, so treat any single average with suspicion. The same sixteen-year-old added to the same policy structure produces a very different bill in Baton Rouge than in Honolulu, and the reason is regulatory rather than behavioural.
Hawaii is the extreme case and it is instructive: state law there prohibits insurers from rating on age, sex, or length of driving experience, so a newly licensed teen cannot be surcharged simply for being new. Every other state prices youthful drivers as the highest-risk category on the road, and that risk is genuine — crash rates per mile are dramatically higher in the first year of independent driving than at any later point in life.
What you control is narrower than the sticker shock suggests, but it is not nothing. Vehicle assignment, discount capture — particularly the home-and-auto bundle — and carrier selection routinely move the number by a meaningful margin. Expect the increase to be largest in year one and to decline at each renewal as your teen accumulates a clean record.