Cash Back vs. Low Interest: Which is Better?
When purchasing a new vehicle, auto manufacturers frequently offer incentives to boost sales. The two most common promotions are a cash back rebate or a low-interest (or 0%) financing rate. Because these deals are almost always mutually exclusive, you are forced to choose one or the other. Using the Cash Back or Low Interest Calculator helps you make the optimal financial decision by calculating the true total cost of both scenarios.
How Cash Rebates Work
A vehicle cash rebate is a direct deduction from the negotiated purchase price of the car. These generally range from a few hundred dollars up to several thousand. In many cases, the cash back can be applied directly toward your down payment, meaning you need less cash out of pocket on the day of purchase.
Rebates reduce the overall principal balance of your loan. However, you will have to finance that remaining balance at the dealer's standard (or "high") interest rate, or secure financing from a third-party bank or credit union.
How Low-Interest Financing Works
Low-interest or 0% APR financing means the dealer's captive lender is subsidizing your loan rate. Over the life of a 5-year or 6-year loan, paying 0% instead of 5% or 7% can save you thousands of dollars in interest charges. However, you will forfeit the cash rebate, meaning your starting principal balance will be higher.
It is also important to note that low-interest financing is generally reserved for "well-qualified buyers" with top-tier credit scores. If your credit is average or poor, you might not qualify for the promotional rate and will be better off taking the cash back.
The Financial Formula
To determine the true winner, we calculate the total out-of-pocket cost for both paths. This includes the upfront payments (down payment, taxes, fees) plus the sum of all monthly loan payments.
PMT = P × [ r(1 + r)^n ] / [ (1 + r)^n - 1 ]
Where:
P = Principal Loan Amount
r = Monthly Interest Rate (Annual Rate / 12)
n = Total Number of Months
If the Total Cost with Cash Back < Total Cost with Low Interest, you should take the rebate. Otherwise, opt for the financing promotion.
Frequently Asked Questions
It depends on your state. Most U.S. states calculate sales tax based on the vehicle price before the manufacturer cash rebate is applied. A few states (like Alaska, Delaware, and Oregon) have no sales tax, while others (like Texas and Pennsylvania) don't tax the rebate amount. Our calculator computes tax based on the full purchase price before the rebate for a conservative estimate.
Not always. While 0% sounds unbeatable, if the cash rebate is large enough and the loan term is relatively short, the immediate principal reduction from the rebate might save you more money than the interest you avoid with 0% financing. You must run the math to be sure.
Yes, usually. If you choose the cash back rebate, you can often bring your own financing from a local credit union or bank. If your credit union offers a lower interest rate than the dealer's "standard" rate, you can maximize your savings by taking the manufacturer's rebate and the credit union's lower rate.
Yes. If you check the "Include Taxes & Fees in Loan" box in our calculator, the upfront costs are rolled into the financed principal. This means you will pay zero out of pocket for tax and registration, but your loan amount and monthly payments will increase, and you will pay interest on those fees.
No. Highly advertised low or 0% interest rates are primarily marketing tools used to get buyers into the showroom. They usually require excellent credit (typically a FICO score of 720+). If you don't qualify, the dealer may offer you a higher rate, at which point the cash rebate becomes the obvious choice.