Free cash back or low interest calculator
Enter the vehicle price, cash rebate, and promotional APR — this calculator compares total cost both ways to show whether the cash back or low interest offer saves you more, updated live, as you type.
On this page10 sections
Flat-rate cash back only. Excludes card fees, bonuses, or tiered category rates. Compare total value with any annual fee.
Results are estimates. Consult a professional.
How the cash-back vs. low-interest calculator works
Car dealers and manufacturers routinely offer two mutually exclusive incentives: a cash rebate that reduces the purchase price, or a promotional (often 0%) financing rate. The best choice depends on your market interest rate, loan term, credit score, and the size of the rebate. This calculator finds the total cost of each option and shows which saves you more money.
The rebate wins when the interest saved by financing a lower balance (Option A) exceeds the rate savings from the promo APR (Option B). At market APRs above roughly 5–6%, a substantial cash rebate almost always wins. At 0% financing, the promo rate wins unless the rebate is very large relative to the loan amount.
Bankrate auto loan guide 2024; NerdWallet car rebate vs. financing analysisWorked example: $3,000 rebate vs. 0% for 60 months
Vehicle price: $35,000. Down payment: $3,000. Rebate (Option A): $3,000 applied to price. Market APR (Option A): 7.5%. Promotional APR (Option B): 0%. Term: 60 months.
Break-even market APR: when does the cash rebate beat the 0% promo rate?
The table below shows the market APR at which both options cost exactly the same — below that rate, take the cash back; above it, take the 0% financing. Figures assume a $35,000 vehicle, $3,000 down, and a 60-month term.
| Cash Rebate | Break-Even Market APR | Monthly Savings at 7.5% Market Rate |
|---|---|---|
| $2,500 | 4.38% | $45/mo (0% wins) |
| $3,500 | 6.19% | $29/mo (0% wins) |
| $5,000 | 9.10% | Cash back wins by $14/mo |
Source: Bankrate 2024; NerdWallet rebate-vs-financing tool. Calculations assume no fees, taxes excluded.
Rule of thumb: if your credit score qualifies you for rates below 4%, cash rebates become attractive faster. If you're paying 7%+ in the open market (common for scores below 720), the 0% promo rate almost always wins on loans over 48 months.
Tips for choosing between cash back and low-interest financing
The math is straightforward, but a few real-world factors can shift the decision. Run the numbers with your actual credit union or bank rate before stepping into the dealership — not a rough estimate.
- Get pre-approved before the dealer conversation — your pre-approval rate is the 'market APR' to use in this calculator. Dealer-arranged financing is often marked up 1–2 percentage points above the buy rate.
- Check whether the rebate is stackable — some manufacturers allow you to combine a cash rebate with loyalty or military bonuses; others require you to choose one incentive. Ask for the full incentive disclosure form.
- A shorter loan term shifts the math — on a 24-month term, even a modest rebate often beats a promo rate because total interest is already low. Run the calculator with your actual term.
- Factor in opportunity cost if paying a large down payment — if you were planning a $5,000 down payment, consider whether that cash is better held in a high-yield savings account while you finance at 0%.
- Watch for promo-rate eligibility requirements — 0% and 1.9% promotional rates typically require a credit score of 720+ and financing through the manufacturer's captive lender. If you're borderline, get a written rate commitment before turning down the rebate.
Accuracy and limitations
This calculator uses the standard amortization formula and produces results accurate to within a few dollars of a lender's payment schedule, provided you enter your actual negotiated price, market APR, and term. Small differences may appear if the lender uses a different day-count convention or rounds the monthly payment up to the nearest cent.
The calculator does not account for sales tax (which may be calculated on the pre-rebate or post-rebate price depending on your state), dealer fees, or the tax deductibility of auto loan interest for business-use vehicles. In some states, sales tax is applied to the full purchase price even when you take a cash rebate, which can marginally reduce the rebate's advantage. Consult a tax advisor for business-use vehicles.
Cash-back vs. low-interest terms defined
About this cash-back vs. low-interest calculator
This calculator runs entirely in your browser — nothing you enter is sent to any server.
Browse more in our automotive calculators, or explore the complete library on the free calculators page.