How does the calculator weigh a rebate against a promotional rate?
It builds two loans with the same down payment and term. The rebate loan is the price minus the down payment minus the rebate, financed at the rate you would get from your own lender. The promotional loan is the price minus the down payment, financed at the dealer's low rate.
For each, it computes the fixed monthly payment and the total cost: the down payment plus every payment over the term. The option with the lower total is labeled Best Option, and the gap between the totals is what you save.
With the same term on both sides, the option with the lower payment is also the one with the lower total. The payment gap can look trivial, though, while the total gap runs to hundreds of dollars, which is why the calculator shows both. If a dealer quotes the two offers on different terms, rerun them on one term before comparing.
Rebate loan = Price − Down − Rebate, at outside rate Promo loan = Price − Down, at promotional rate Total cost = Down + M × n (for each option) You save = |Total(rebate) − Total(promo)|
- M
- monthly payment for each loan from the standard amortization formula
- n
- loan term in months, the same for both
Example: $3,000 cash back or 1.9% financing on a $38,000 car
Scenario: A buyer putting $4,000 down on a $38,000 car for 60 months can take a $3,000 rebate and finance at 6.75% through a credit union, or skip the rebate and finance at a 1.9% promotional rate.
- Rebate loan amount$38,000 − $4,000 − $3,000 = $31,000.00
- Rebate option payment$31,000.00 at 6.75% for 60 months = $610.19
- Promo loan amount$38,000 − $4,000 = $34,000.00
- Low-APR option payment$34,000.00 at 1.9% for 60 months = $594.46
- Total costsRebate: $4,000 + $610.19 × 60 = $40,611.40; Promo: $4,000 + $594.46 × 60 = $39,667.60
- Difference$40,611.40 − $39,667.60 = $943.80
The promotional rate is the better deal here, costing $943.80 less than taking the rebate.
The rebate would win if the buyer's outside rate were below about 5.66%.
When should you run a rebate-versus-APR comparison?
An advertised incentive gives you a choice
Manufacturer offers often present cash back and special financing as alternatives. Run both before you sit down with the finance office.
You have a preapproval in hand
A bank or credit union preapproval tells you the rate to enter for the rebate option. Without it, the comparison rests on a guess.
You are deciding on a term
Promotional rates may only apply to certain terms. Compare the offers at the term you would actually choose, not just the one in the ad.
You might pay off the loan early
If you plan to pay off the loan quickly, the low rate matters less and the rebate's price cut matters more. Try a shorter term to approximate that.
Which rebate-versus-financing mistakes are common?
Comparing offers on different terms
A promotional rate quoted at 36 months and a rebate loan at 72 months cannot be compared by payment. Put both on the same term, then compare totals.
Using an optimistic outside rate
Entering a rate you have not been approved for makes the rebate look better than it is. Use an actual quote.
Assuming you qualify for the promotional rate
Promotional financing is often reserved for top credit tiers. Confirm you qualify before counting on it.
Letting the price creep up
Negotiate the price first, then choose the incentive. An incentive is worth less if the price rises to absorb it.
Forgetting how the rebate is taxed
In some states sales tax is charged on the price before a manufacturer rebate is applied. That does not change this comparison much, but it affects your out-the-door cost.
At what outside rate does the rebate start to win?
The rate you can get elsewhere decides this comparison, so it is worth seeing the break-even point. The table keeps the example's price, down payment, rebate, term and 1.9% promotional rate fixed and changes only the outside rate on the rebate loan.
With these numbers, the rebate wins only if you can borrow below about 5.66%. On a shorter 36-month term, the same offers produce payments of $953.65 for the rebate and $972.36 for the promo, and totals of $38,331.40 versus $39,004.96. The rebate wins by $673.56 there, because the low rate has fewer months in which to outweigh the cash back.
| Outside rate (rebate option) | Rebate payment | Rebate total cost | Promo total cost | Lower cost |
|---|---|---|---|---|
| 3% | $557.03 | $37,421.80 | $39,667.60 | Rebate |
| 4% | $570.91 | $38,254.60 | $39,667.60 | Rebate |
| 5% | $585.01 | $39,100.60 | $39,667.60 | Rebate |
| 6% | $599.32 | $39,959.20 | $39,667.60 | Promo APR |
| 6.75% | $610.19 | $40,611.40 | $39,667.60 | Promo APR |
| 8% | $628.57 | $41,714.20 | $39,667.60 | Promo APR |
Terms used on this page
- Promotional APR
- A promotional APR is a temporary, reduced interest rate, often 0%, that a card issuer offers for a set period on purchases, balance transfers or both. When the promotion ends, any remaining balance is charged the card's regular APR. It can save real money if you plan to pay the balance off within the window.
- APR (Annual Percentage Rate)
- APR is the yearly cost of borrowing expressed as a single percentage that includes the interest rate plus certain required fees, such as origination charges. Because lenders must calculate it the same way under federal Truth in Lending rules, APR lets you compare loan offers on an even footing.
- Loan Term
- The loan term is the length of time you have to repay a loan, usually stated in months for consumer loans. A longer term lowers the monthly payment but increases the total interest you pay, because the balance stays outstanding longer. A shorter term costs more each month and less overall.
- Down Payment
- A down payment is the cash you pay upfront toward a purchase, such as a car or home, so you borrow less. A larger down payment reduces the loan principal, the monthly payment and total interest, and it lowers the chance of owing more than the item is worth. It can also help you qualify for a better rate.
Rebate vs. Low APR Calculator: common questions
Can you get both a rebate and a low APR?
Sometimes, but usually not. Many manufacturer offers make cash back and special financing alternatives, though some combine a smaller rebate with a promotional rate. Read the offer terms or ask the dealer which incentives can be stacked for the specific vehicle and term. When only one can be used, this calculator shows which saves more for your rate, term and down payment.
Is 0% financing better than cash back?
Zero-percent financing is often better on larger loans and longer terms, because it removes all interest. A large rebate can still win if your outside rate is low or the term is short. Enter 0 as the promotional rate to compare it directly. Zero-percent offers are also frequently limited to shorter terms, which raises the monthly payment even though no interest is charged.
How do I compare a rebate with low APR financing?
Build both loans with the same down payment and term: the rebate loan at your outside rate and the full-price loan at the promotional rate. Add the down payment to every payment for each and compare totals. This calculator does that in one step. Use a rate you have actually been approved for on the rebate side, because the answer is sensitive to it, and keep the term identical for both offers.
Should I take the rebate if I plan to pay off the car early?
The rebate often looks better if you will pay the loan off quickly, because you keep its full value while carrying the higher rate for only a short time. The promotional rate's advantage builds over the full term. Try a shorter term in the calculator to model an early payoff.
Can I take the rebate and then pay cash?
Yes, if you pay cash, the rebate is usually the clear choice, since a low financing rate is worth nothing without a loan. Just confirm that the rebate does not require dealer financing to qualify. If you would rather keep cash invested, financing at the promotional rate might still make sense, but compare the after-tax return you expect with the rebate's guaranteed value first.
Why does the promotional loan have a higher balance?
Because you give up the rebate to get the low rate, you finance the full price minus your down payment. The rebate loan starts smaller by the rebate amount. That is the trade-off: a smaller loan at a higher rate versus a larger loan at a lower one. Because interest is charged on a larger balance, the promotional rate must be low enough to overcome that extra principal for it to win.
Do promotional auto rates require good credit?
Usually. Special manufacturer financing is often limited to borrowers in the top credit tiers, and those who do not qualify may be offered a higher rate. Ask whether you qualify before choosing between offers. Checking your credit reports for errors before you shop can help, and a preapproval from your own lender tells you what rate to enter for the rebate option.
Is sales tax charged before or after a car rebate?
It depends on the state. Some tax the price before the manufacturer rebate is deducted, others after. This calculator assumes tax and fees are equal under both offers, so check your state's rule when estimating your total out-the-door cost. When a state taxes the pre-rebate price, the rebate saves you less than its face value would suggest, because tax is still owed on that amount.
Sources
- Auto loans — Consumer Financial Protection Bureau. Accessed October 17, 2026.
- Regulation Z (Truth in Lending), 12 CFR Part 1026 — Consumer Financial Protection Bureau. Accessed October 17, 2026.
- Credit reports and scores — Consumer Financial Protection Bureau. Accessed October 17, 2026.
We cite primary sources: regulators, central-bank data and federal agencies. Worked examples on this page are our own calculations, last checked October 17, 2026. See our methodology.