Does this calculator include taxes and fees?

No. It focuses on comparing principal, rate, and term across two financing options. To improve accuracy, you can add taxes and fees to the vehicle price, but be consistent across both scenarios.

What if I plan to pay off the loan early?

This calculator assumes you keep the loan for the full term. If you expect to pay it off early, the effective difference between the two options may shrink. You can approximate by using a shorter term that matches how long you expect to keep the loan.

Is 0% APR always better than a rebate?

Not always. A large rebate at a higher APR can sometimes beat 0% APR with no rebate, especially on shorter terms. Running the numbers is the best way to know.

finance calculator

Cash Back or Low Interest Calculator

Compare taking a cash rebate with a higher APR vs. skipping the rebate for a low-interest offer to see which car deal costs less overall.

Results

Loan amount with rebate: $27,000 USD
Monthly payment with rebate: $528 USD
Total paid with rebate: $31,697 USD
Total interest with rebate: $4,697 USD
Loan amount with low-interest offer: $30,000 USD
Monthly payment with low-interest offer: $538 USD
Total paid with low-interest offer: $32,264 USD
Total interest with low-interest offer: $2,264 USD
Better deal (rebate vs low-interest): rebate
Estimated savings vs other option: $567 USD

Overview

Auto dealers often advertise a choice: take a cash rebate with a higher APR, or skip the rebate and get low-interest financing. The better deal isn’t always obvious. This calculator compares both options side by side—loan amounts, monthly payments, total interest, and total paid—so you can see which one actually costs less over the life of the loan.

How to use this calculator

Enter the vehicle price and the available cash rebate.
Enter your planned down payment, which applies in both scenarios.
Enter the APR you’d pay if you take the rebate, and the promotional APR if you skip the rebate.
Enter the loan term in years.
Review loan amounts, monthly payments, total paid, and total interest for each option, plus which option costs less and by how much.

Inputs explained

Vehicle price: The agreed purchase price of the vehicle before rebates and down payment. Taxes and fees are not included in this simple comparison.
Cash rebate: The lump-sum discount you receive if you choose the rebate offer. This reduces the loan amount in the rebate scenario.
Down payment: Cash you pay upfront in either scenario. It reduces the loan amount for both options equally.
APR with rebate: The interest rate you’ll pay if you take the cash rebate. This is often a standard or higher APR compared to promotional low-interest offers.
APR with low-interest offer: The promotional interest rate you can get if you decline the cash rebate. This is usually lower than the standard rate, but you finance a higher principal.
Loan term: The length of the loan in years. Longer terms reduce monthly payments but increase total interest in both scenarios.

Outputs explained

Loan amount with rebate: The principal you would finance if you take the cash rebate: vehicle price minus rebate minus down payment.
Monthly payment with rebate: Your estimated monthly payment under the rebate scenario based on that loan amount, APR, and term.
Total interest with rebate: How much interest you’d pay over the full term if you take the rebate offer.
Loan amount with low-interest offer: The principal you would finance if you skip the rebate and take the low-interest offer: vehicle price minus down payment.
Monthly payment with low-interest offer: Your estimated monthly payment under the low-interest scenario.
Total interest with low-interest offer: How much interest you’d pay over the full term if you decline the rebate and choose the low APR.
Better deal: Indicates which option (rebate or low-interest) has the lower total paid over the life of the loan.
Estimated savings: The difference in total paid between the more expensive and cheaper option. A positive number shows how much you save by choosing the better option.

How it works

You enter vehicle price, the cash rebate amount, your down payment, both APRs, and the loan term.

For the rebate scenario, the loan amount is vehicle price minus rebate minus down payment; the APR used is the rate associated with taking the rebate.

For the low-interest scenario, the loan amount is vehicle price minus down payment (no rebate); the APR used is the promotional low-interest rate.

The calculator converts APRs to monthly rates and applies the standard amortization formula in each scenario to compute monthly payment, total paid, and total interest.

It then compares total paid between the two options and flags which one is cheaper overall, along with estimated savings versus the more expensive option.

If one APR is 0%, it simplifies that scenario to principal divided evenly across the number of months.

Formula

Rebate scenario:
  LoanRebate = Price − Rebate − DownPayment
  r_std = APR_with_rebate ÷ 100 ÷ 12
  n = TermYears × 12
  If r_std > 0:
    PaymentRebate = LoanRebate × [r_std(1 + r_std)^n] ÷ [(1 + r_std)^n − 1]
  Else:
    PaymentRebate = LoanRebate ÷ n
  TotalPaidRebate = PaymentRebate × n
  TotalInterestRebate = TotalPaidRebate − LoanRebate

Low-interest scenario:
  LoanLow = Price − DownPayment
  r_promo = APR_low_interest ÷ 100 ÷ 12
  PaymentLow, TotalPaidLow, TotalInterestLow computed similarly.

Better option is the one with the lower TotalPaid.

When to use it

Comparing dealer incentives like “$3,000 cash back OR 2.9% APR” before you visit the showroom.
Stress-testing deals offered by different dealerships or lenders for the same vehicle.
Checking whether a flashy 0% APR deal is actually better than a large rebate at a higher APR.
Explaining financing trade-offs to a co-buyer or family member when making a decision together.

Tips & cautions

Run the calculator with your real numbers from the purchase agreement—small changes in rate or rebate size can flip which option is better.
Consider how long you actually plan to keep the loan; if you expect to pay it off early, the lower APR may matter less than a large rebate upfront.
Remember to factor taxes, fees, and any add-ons (like warranties) into your buying decision even though this simplified model excludes them.
Assumes both loans are fully amortized over the same term with fixed monthly payments and no prepayments.
Does not include taxes, fees, dealer add-ons, or prepayment penalties.
Does not model changes in rate, refinancing, or paying the loan off early.

Worked examples

Example: $30,000 car, $3,000 rebate at 6.5% vs 2.9% promo

Price = $30,000; Rebate = $3,000; Down = $0; Term = 5 years.
Rebate option: LoanRebate = $27,000 at 6.5% APR.
Low-interest option: LoanLow = $30,000 at 2.9% APR.
The calculator computes payments and totals for both and shows which produces the lower total paid and by how much.

Example: 0% APR vs large rebate

If the low-interest offer is truly 0% APR, you’ll repay only principal in that scenario.
The rebate option still incurs interest but starts with a smaller loan amount.
The calculator helps you see whether the rebate is large enough to beat 0% financing.

Deep dive

Use this cash back or low-interest calculator to compare taking a cash rebate with a higher APR versus skipping the rebate for low-interest financing.

Enter vehicle price, rebate, APRs, and term to see loan amounts, monthly payments, total interest, and which option costs less overall.

Great for car buyers who want to cut through dealer marketing and choose the truly cheaper financing offer.

FAQs

Does this calculator include taxes and fees?: No. It focuses on comparing principal, rate, and term across two financing options. To improve accuracy, you can add taxes and fees to the vehicle price, but be consistent across both scenarios.
What if I plan to pay off the loan early?: This calculator assumes you keep the loan for the full term. If you expect to pay it off early, the effective difference between the two options may shrink. You can approximate by using a shorter term that matches how long you expect to keep the loan.
Is 0% APR always better than a rebate?: Not always. A large rebate at a higher APR can sometimes beat 0% APR with no rebate, especially on shorter terms. Running the numbers is the best way to know.

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This cash back vs low-interest calculator provides simplified estimates and does not include taxes, fees, add-ons, or prepayment behavior. Actual loan terms and costs may differ. Always review dealer and lender disclosures carefully and consult a financial professional if you need personalized advice.