A CarMax offer is good for 7 days, whether you got it online in a couple of minutes or in person at a store. The number itself is the same either way, and CarMax will pay it whether or not you buy a car from them. What most sellers don't realize: the 7-day clock can effectively be reset once, and what happens after day 7 is a brand-new appraisal that can come back lower.
I'm Joe, a licensed California dealer. Sellers call me every week holding a CarMax offer, usually somewhere around day 4 or 5, trying to decide what to do with it. So here is exactly how the window works, straight from CarMax's own published policy, and how to use those 7 days well.
Quick answer:
- The window: 7 days from the date the offer is issued, online or in-store.
- Online vs. in-store: same number, same validity. The online offer is a real offer, not an estimate, but it's contingent on the car matching what you described.
- The reset: complete the in-person verification on or before day 7 and the written offer is good for 7 days from the verification date. Used well, that's roughly two weeks of coverage.
- After it expires: no extensions. You start over with a new appraisal, and the new number follows the market up or down.
- Can it change? Only if the verification finds something you didn't disclose: condition, mileage, accident history.
- Can you negotiate it? No. The price is set by their system, and store associates can't raise it.
Is the CarMax online offer a real offer or an estimate?
It's a real offer. CarMax is explicit that the number you get online is the same one you'd get at the store, and that they'll buy your car "even if you don't buy ours" (carmax.com). The contingency is verification: the offer assumes the car's condition, mileage, and history match what you entered (carmax.com FAQ).
That verification is the part sellers underestimate. If the car shows up with a warning light you didn't mention, more miles than you entered, or an accident that didn't make it into the form, the offer gets adjusted. If your disclosures were accurate, the number holds. In my experience talking to sellers who've been through it, the offer holding is the normal case, and the adjustment stories almost always trace back to something that wasn't disclosed.
Worth knowing about the mileage piece: there isn't a published per-mile allowance. The offer is tied to the condition and mileage you declared, so a road trip between quote and verification is the kind of change that gets the number relooked. If you're going to drive the car normally for a week, that's not a problem. Don't take it to Vegas twice.
How the 7-day clock actually works
Here's the timeline that matters if you're using the offer the smart way:
| Day | What's happening |
|---|---|
| Day 0 | You get the offer (online takes a few minutes; in-store follows the appraisal) |
| Days 1 to 6 | The number is locked. This is your shopping window: get competing bids against it |
| Day 7 | Last day. If you started online, completing the in-store verification issues a written offer good for 7 days from THAT date |
| After expiry | The offer is gone. No extensions; you request a new appraisal and take whatever the current market says |
Two details inside that table deserve emphasis.
The day-7 reset is real, and it's the only extension mechanism that exists. Stores don't grant grace periods on expired offers. But an online offer verified in person on day 7 becomes a fresh written offer with its own 7-day life, which is how a well-timed seller stretches one quote into roughly two weeks of decision time (carmax.com).
After expiry, you're not renewing, you're re-rolling. The new appraisal follows current market data for your car, which can be higher but is often flat to lower, and repeat submissions don't stack in your favor. CarMax even built a tool around this reality: Offer Watch, introduced in late 2025, lets you track how your car's estimated value moves over time so you can time a fresh appraisal instead of guessing (CarMax investor news). Read that as confirmation from CarMax itself: the number is a snapshot of a moving market, not a standing promise.
One more update from that same announcement, in fairness to them: CarMax now offers at-home pickup nationally, so in many cases you no longer have to drive to a store to hand the car over. The offer window rules above don't change; the handoff logistics did.
Don't want to read the rest? Get a real number instead.
Tell Joe the basics. He calls or texts within 2 hours with what he'd actually pay for your car. Guaranteed to match or beat any CarMax offer.
Not ready to call? No problem.
Tell me about your car. I’ll text or call you back within 2 hours with a realistic range.
What should you do with your 7 days?
Use the window as leverage. A CarMax offer is the single most useful piece of paper in a car sale, not because it's the most money, but because it's a firm, written, verifiable number that every other buyer has to answer to. My advice, and I say this as one of the buyers who has to answer to it:
- Get the offer early, not when you're desperate. The clock only helps you if you have time to use it. If you're starting from zero, here's how the whole CarMax selling process works.
- Shop it immediately. Days 1 through 6 are for collecting competing bids: Carvana, a local dealer, whoever. If you want the honest comparison of how those buyers stack up, I wrote up CarMax vs. Carvana for selling.
- Don't burn day 7 in a waiting room. If you're going to verify in person to reset the clock, know what the appraisal appointment actually involves before you go.
- Remember the number is a ceiling for them and a floor for you. CarMax won't negotiate up; associates can't raise it (more on that here). But any other buyer can beat it.
That last point is where I come in. My offer is guaranteed to match or beat any CarMax offer, and I make it at your driveway. So the play that costs you nothing: get the CarMax number, then call or text me at (818) 325-7535 before it expires. You either confirm CarMax was the right answer, or you beat it without driving anywhere. And unlike a number generated by an algorithm a week ago, the price I quote at your curb is the price you get, checked against the car in front of me, the day you're actually selling.
Frequently asked questions
How long is a CarMax offer good for?
Seven days from the date it's issued, whether you got it online or at a store. After that it expires and you'd need a new appraisal.
Is the CarMax online offer the same as the in-store offer?
Yes. CarMax states the number is the same online and in person, and the same whether you sell outright, trade in, or buy nothing from them. The online offer is contingent on in-person verification that the car matches what you described.
Does CarMax extend offers past 7 days?
No. Stores don't extend expired offers. The one legitimate way to get more time: complete the in-person verification before the online offer expires, which issues a written offer good for 7 days from the verification date.
What happens if my CarMax offer expires?
You request a new appraisal and get a new number based on the current market for your car. It can come back higher or lower than the old one, and often it's flat to lower. The expired number is not honored.
Can CarMax lower the offer when I bring the car in?
Only if the verification finds a mismatch with what you disclosed: condition problems, different mileage, warning lights, or history issues like unreported accidents. If your online answers were accurate, the offer stands. It also doesn't negotiate upward; the price is set by their system.
Will another buyer beat a CarMax offer?
Sometimes, and it costs nothing to find out while your 7 days run. CurbSold's offer is guaranteed to match or beat any CarMax offer, made at your door with same-day payment, so the CarMax number works as your verified floor.