Cash Back or Low Interest Calculator · Practical guide
Should I Take the Rebate or Lower Interest Rate?
Compare total cost, not monthly payment — the answer flips depending on the rebate size and the rate gap.
At a glance
The short answer
Compare the total cost of both paths, not the payments. On a $30,000 car over 48 months with a 5% standard rate, a 0.9% promo beats a $1,000 rebate by about $1,502 — but raise the rebate to $2,500 and the rebate wins by about $156.
| $30,000 Car, 48 Months, 0.9% Promo vs 5% Standard | Rebate Path Total | Promo Rate Total | Winner |
|---|---|---|---|
| $1,000 rebate | $32,057 | $30,554 | Low rate by $1,502 |
| $2,500 rebate | $30,399 | $30,554 | Rebate by $156 |
Interactive tool
Cash Back or Low Interest Calculator
Enter your own values, then compare the result with the examples below.
Results
The break-even logic
The promo rate saves you interest on the full price; the rebate shrinks the principal but you still pay the standard rate on what remains. The promo wins when the interest saved exceeds the rebate. Bigger rebates, smaller rate gaps, and shorter terms all tilt the math toward cash back.
Why monthly payments mislead
In the $1,000 rebate case, the payment difference is small — about $668 versus $637 per month. Looking only at payments makes the choice feel trivial, yet the totals differ by $1,502. Always run the full cost over the term.
How to decide on your own deal
Get your real standard rate from a bank or credit union before visiting the dealer — that number is half the equation. Then enter the negotiated price, the rebate, both rates, and the term above. The calculator shows both totals and names the cheaper option outright.
Frequently Asked Questions
Can I take both the rebate and the special rate?
Almost never. Manufacturers structure these as either-or incentives. Occasionally a smaller rebate can combine with a promotional rate — read the offer terms carefully.
What if I plan to pay the loan off early?
Early payoff shrinks the interest the promo rate saves you, which tilts the decision toward the rebate. The faster you will pay it off, the more attractive cash back becomes.
Does my down payment change the comparison?
A larger down payment shrinks the financed amount, which reduces the interest advantage of the promo rate. With very large down payments, the rebate often comes out ahead.
Are dealer rebates taxable?
Treatment varies by state — some tax the price before the rebate, others after. Either way it applies to both financing paths, so it rarely changes which option wins.