Insurance sent me a check way more than the actual repair cost — do I keep the difference?

Totally normal situation and you're not doing anything wrong. When we cut a check, it's based on the cost to restore the vehicle to pre-loss condition — parts AND labor at shop rates. What you do after that is your business. If you fix it cheaper by doing it yourself, that's your reward for the effort. The only time it gets complicated is if you have a lienholder (like a bank that owns part of your car through a loan) — they sometimes have to be on the check and may want proof of repairs. If you own the car outright, you're generally fine.

The one thing worth double-checking is whether your policy or the check itself has any language requiring you to actually use the funds for repairs and submit receipts. Most personal auto policies don't require that for smaller claims on vehicles you own free and clear, but some do. Just skim the claim paperwork they sent you. If there's no such clause, you're in the clear — the check is indemnification for your loss, full stop.

Do you have a loan or lease on the vehicle? That changes things a bit. Lienholders are usually listed as co-payees on insurance checks above a certain amount, and they may require repair documentation before they'll endorse it. If it's your car free and clear, everyone else is right — not a problem. But worth clarifying.

I'd just be careful about calling your insurer to 'do the right thing' and tell them you fixed it cheaper. Some people think that's the honest move and it is, kind of — but there's a real chance the adjuster then tries to claw back the difference or flags your file. You fixed the car. The claim is closed. I wouldn't reopen that conversation voluntarily.

Honestly I think you're overthinking it! You got debris thrown at your car through no fault of your own, you dealt with the hassle of filing a claim, took time to go to a shop, and then did the repair work yourself. That's not fraud — that's just being resourceful. Glad your car is back in one piece.

Not legal advice, but generally speaking: an insurance payment is meant to make you 'whole' after a covered loss. If you achieve that result for less than the estimate, courts and regulators don't typically view keeping the difference as fraud — you repaired the damage as required. The fraud concern would arise if the car was not actually fixed and you pocketed the money while hiding ongoing damage. Since you fixed it, you should be fine. If your state or policy has specific requirements, a quick consult with a local PI attorney can confirm.