Every lemon law buyback calculator runs on the same basic math: add up what you’ve paid toward the car, then subtract a mileage offset. The offset equals the miles on the odometer at your first repair visit for the defect, divided by 120,000, multiplied by the price you paid for the vehicle.
The formula is simple. Getting the inputs right is not. Most self-estimates come in low because they plug in the wrong mileage or leave out costs the law lets you recover. Here’s how to run the numbers yourself, and where to double-check them.
Estimate your buyback
Enter the numbers from your purchase contract and repair orders. Everything stays on this page.
The manufacturer also pays off any remaining loan or lease balance directly to your lender.
Get your number reviewed for free
Illustrative estimate only, not legal advice. It uses the statutory mileage offset formula (miles at first repair visit ÷ 120,000 × vehicle price) and can’t account for disputed line items, civil penalties, or whether your vehicle qualifies. Prior results do not guarantee a similar outcome.
What goes into a lemon law buyback calculator?
California's lemon law, formally the Song-Beverly Consumer Warranty Act, spells out what a manufacturer repurchase has to cover. Under Civil Code section 1793.2, the refund is built from the price paid or payable, plus collateral charges and incidental costs.
For a working estimate, gather these numbers:
- Down payment, including any trade-in credit
- Monthly payments made so far, interest included
- Remaining loan or lease payoff, which the manufacturer pays to your lender
- Registration renewals and other official fees you paid separately
- Incidental costs tied to the defect: towing, rental cars, out-of-pocket repairs
- Price paid for the vehicle, for the offset calculation
- Odometer reading at your first repair visit for the defect
Your purchase contract covers most of the list. Your repair orders cover the rest. If you don't have copies, the dealer's service department can print your repair history.
How The Mileage Offset Formula Works
The offset is the one deduction the statute allows. It's the manufacturer's credit for the miles you drove before the defect first sent the car in for repair.
(Miles at first repair visit for the defect ÷ 120,000) × price paid for the vehicle
Three rules keep the calculation honest:
- Use the first repair visit, not today's mileage. The odometer reading that counts is the one on the first repair order for the problem at the center of your claim.
- The divisor is always 120,000. It doesn't change for electric vehicles, hybrids, or luxury models.
- The price is the vehicle's price. What belongs in that figure is one of the most argued points in any repurchase, and it's covered below.
The 120,000 divisor has nothing to do with the 18,000-mile window you may have read about. That window, part of the Tanner presumption in Civil Code section 1793.22, affects whether a presumption applies within 18 months of delivery or 18,000 miles, whichever comes first. Outside it, a claim can still succeed. The offset math is a separate question entirely.
A worked example, step by step
These numbers are illustrative only. They aren't from any real case, and your figures will differ.
Say you bought a new SUV for a vehicle price of $45,000. You put $5,000 down and have made 20 payments of $750. The check engine light and a stalling problem first sent it to the dealer at 7,200 miles. Today it shows 24,000 miles, and it's been back four more times.
Here's the calculation:
- Offset: 7,200 ÷ 120,000 = 0.06. Then 0.06 × $45,000 = $2,700.
- What you've paid: $5,000 down + $15,000 in payments = $20,000.
- Other recoverable costs: a $450 registration renewal, plus $600 in rental and towing = $1,050.
- Your refund: $20,000 + $1,050 − $2,700 = $18,350.
- Lender payoff: the manufacturer separately pays your remaining loan balance, say $26,000.
In this example, the manufacturer's total cost is $44,350. You walk away with $18,350 and no car payment.
Not sure which repair order counts as your first visit? A free case review costs nothing, and Mathew or Eli can pull the right number from your paperwork.
Why DIY Estimates Often Come In Low
Run the same example the way most owners do on their own, and the number drops fast.
| Input | Typical DIY estimate | Reviewed estimate |
|---|---|---|
| Mileage used for offset | 24,000 (today) | 7,200 (first visit) |
| Mileage offset | $9,000 | $2,700 |
| Registration renewal | Left out | $450 |
| Rental and towing | Left out | $600 |
| Refund to you | $11,000 | $18,350 |
Same car, same contract, and a $7,350 gap. Nothing in the reviewed column is aggressive. It's just the statute applied to the right documents.
The most common reasons a DIY number runs short:
- Wrong mileage. Using current miles instead of the first repair visit.
- A missed earlier visit. An early repair order for the same symptom, even one marked "could not duplicate," may set a lower offset mileage.
- An inflated price. Using the full contract total, finance charges and add-ons included, as the offset base.
- Forgotten costs. Registration renewals, rental cars, towing, and repairs you paid for yourself.
A spreadsheet or online lemon law buyback calculator can't catch any of those. It only knows what you type in.
What A Calculator Can't Tell You
The formula estimates a repurchase. It doesn't tell you three things that matter just as much.
Whether your car qualifies. The buyback only applies if the manufacturer failed to fix a substantial warranty defect after a reasonable number of attempts. Our post on California lemon law requirements covers those thresholds.
Whether penalties apply. Under Civil Code section 1794, a willful refusal to honor the law can add a civil penalty of up to two times actual damages. No calculator can predict that.
Which rules govern your claim. Some manufacturers opted into California's newer pre-suit procedures and some didn't. That affects deadlines and process, not the formula, but it changes how you get paid.
What Manufacturers Do With Your Numbers
Manufacturers run their own calculations, and they rarely round in your favor. Here's what to listen for.
"We used the mileage on the buyback date."
That's the wrong reading. The offset is tied to the first repair visit for the defect, and every extra mile they add comes straight out of your refund.
"The offset is based on your total contract price."
Finance charges and dealer add-ons can push that base up. The statute ties the offset to the price of the vehicle, and what belongs in that figure is worth contesting.
"Your first visit didn't count."
A repair order marked "no problem found" can still show when you first reported the defect. Don't let the manufacturer skip past it.
When Should You Bring In An Attorney?
A buyback estimate is only as good as the documents behind it. An attorney reads your contract line by line, matches every repair order to the defect, and checks whether the manufacturer followed the right procedure.
It also costs you nothing out of pocket. Under section 1794, a buyer who prevails can recover attorney's fees from the manufacturer, so those fees aren't deducted from your refund. For a full picture of what a repurchase covers, see our guide to how manufacturer buybacks work.
Frequently Asked Questions
Is there an official lemon law buyback calculator in California?
No. California doesn't publish an official tool. The statute sets the formula, and any online calculator is just applying it to the numbers you enter. That's useful for a rough estimate, but it can't check whether you picked the right repair order or included every recoverable cost. Treat any result as a starting point.
Does the mileage offset apply to leased vehicles?
Generally, yes. On a lease buyback, the manufacturer typically pays off the leasing company and refunds the payments you made, minus the offset. The same 120,000-mile formula applies. The vehicle price used for the offset can be calculated differently on a lease, so it's worth having the lease agreement reviewed.
What if my first repair visit was for a different problem?
The offset uses the first visit for the defect your claim is built on. An earlier oil change or an unrelated repair doesn't set the mileage. If the same symptom shows up under a different description on an early repair order, though, that visit may count. Read every repair order closely.
Should I keep driving the car while I calculate my buyback?
Driving more miles after the first repair visit doesn't increase the statutory offset. Safety comes first, though. If the defect affects braking, steering, or stalling, talk to the dealer and an attorney about whether to keep driving. Keep making your payments either way.
Get Your Number Checked by the Duo
A lemon law buyback calculator gives you a ballpark. The documents decide the real figure, and a few wrong inputs can cost you thousands.
Check the math. Then check it twice. Browse our lemon law FAQ for the basics, or request a free case review, and Mathew or Eli will run your numbers from your contract and repair orders and tell you honestly what the law says you're owed. You pay nothing unless we win, and under California law the manufacturer pays our fees. That's the deal.
This article is general information about California lemon law, not legal advice for any specific situation. Reading it does not create an attorney-client relationship. Case outcomes described are representative examples only; prior results do not guarantee a similar outcome. Every case depends on its own facts and the applicable law. For advice about your vehicle, contact Rezvani Law Firm, APC, DBA The Lemon Law Duo, for a free case review.
