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Finance & LoansBreak-even rate shown

Cash Back vs Low APR Calculator

A rebate is money now; a promotional rate is money spread over years. They are only comparable once both are turned into a single total, which is exactly what the showroom conversation tends to skip.

The Two Offers

Same car, same term — only the incentive differs.

$
$
$
%
%
months
BETTER DEAL SAVES
$2,308
Rebate route — monthly$601/month
Rebate route — total paid$36,068 over 60 months
Promo rate — monthly$563/month
Promo rate — total paid$33,760 over 60 months
Break-even market rate4.75% — below it, take the cash
Monthly difference+$38/month
WinnerTake the promotional rate
On a $38,000 vehicle with $5,000 down: the rebate route finances $30,000 at 7.50% for $36,068 in total, and the promotional route finances the full $33,000 at 0.90% for $33,760. The promotional rate is ahead by $2,308. The crossover is at 4.75%: if you can borrow below that, take the money off the price and finance elsewhere, because cheap borrowing means the interest saved by the promotional rate is worth less than the rebate. Above that rate the subsidised financing wins. That single number is the one worth carrying into the dealership, because your rate is the input most likely to move during the conversation. Note the rebate route has the HIGHER monthly payment here ($601 against $563) even where it costs less overall — a smaller balance at a much higher rate. Judging by the monthly figure alone would point the wrong way. The two incentives are alternatives by design; the finance arm will not give you both, which is why they have to be compared rather than added. Advertised low rates are usually restricted to the top credit tier and sometimes to specific trims being cleared, so confirm which offer you actually qualify for before doing any of this arithmetic. Keep the price negotiation separate from the finance conversation: a monthly payment can always be made to look attractive by lengthening the term. Some states also compute sales tax before the rebate is applied, which trims its value slightly and is not modeled here.

Why the two offers cannot both be taken

Manufacturer incentives are alternatives by design: the rebate comes off the price, the promotional rate comes off the interest, and the finance arm will not give you both. The decision is therefore a straight comparison of two loans — a smaller balance at your normal rate, or a larger balance at a subsidised one.

The break-even rate is the number to remember

There is one market rate at which both routes cost exactly the same. Below it — when you can borrow cheaply anyway — the rebate wins, because a subsidised rate saves you very little interest. Above it, the promotional financing wins. That figure is shown above, and it is the one worth carrying into the dealership, because the rate you are offered is the variable most likely to change during the conversation. Your credit score moves your rate, and the rate moves the answer.

Term length quietly decides it

A rebate is a fixed amount whatever the term. Interest is not: the longer the loan, the more the subsidised rate is worth, so promotional financing looks better at 72 months than at 36. Watch for the trick in that sentence — a longer term also means more months of paying and a higher chance of negative equity, so a deal that wins only because it stretches to six years is not obviously a win.

Promotional rates are not offered to everyone

Advertised 0% deals are typically limited to the highest credit tier and sometimes to specific trims or model years being cleared. If you do not qualify, the real choice is between the rebate and an ordinary loan, which is a different and much simpler question. Ask which of the two offers you have actually been approved for before doing any arithmetic.

Where to finance, and what else changes the price

Nothing obliges you to use the dealer's finance arm when taking a rebate. A pre-approval from your own bank or credit union sets the rate in the first input above and gives you a number to negotiate against. Keep the price negotiation separate from the finance conversation — a monthly payment can be made to look attractive by lengthening the term while the price goes up. Sales tax treatment of rebates also varies by state: in some the tax is computed before the rebate, which reduces its value slightly and is not modeled here.

Frequently Asked Questions

Is 0% financing better than cash back?
It depends on the rate you would otherwise pay and the term. Above the break-even rate above, the promotional financing wins; below it, take the cash and finance elsewhere, because cheap borrowing leaves the subsidised rate with little interest to save.
Can I get the rebate and the low rate?
Almost never. Manufacturers make them alternative incentives, which is why they have to be compared rather than added.
Does a longer loan favor the promotional rate?
Yes. The rebate is a fixed amount, while the value of a lower rate grows with every month of the term — which is also why a long term deserves its own scrutiny.
What if I plan to pay the loan off early?
Early payoff reduces the value of a low rate and leaves the rebate untouched, so it tilts the answer toward the cash. Model it by shortening the term above.
Where these numbers come from

Sources

Official publications only. Links open the original document in a new tab.

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