Cash Back or Low Interest Calculator
Adjust the inputs below. Results update as you type.
How it works
With cash-back: finance (price − rebate) at your bank's rate. With low APR: finance full price at the dealer rate. Compare total interest paid in each scenario. Cash-back is usually better at high dealer rates; low APR wins when the promotional rate is significantly below your bank's offer. Run both scenarios with your actual rate before visiting the dealership.
Input guidance
- Use realistic rates from lender or provider quotes instead of headline averages.
- Model conservative, baseline, and optimistic scenarios before deciding.
- Include recurring real-world costs (fees, taxes, insurance, maintenance) where relevant.
The formula
Compare two offers: the low-rate loan's total cost (payments over the term) versus the cash-back option's loan at the standard rate minus the rebate. The cheaper total wins.
Worked example
On a $30,000 car, a 0% APR for 48 months costs $30,000 total. A $2,500 cash-back deal financing $27,500 at 6% costs more in interest than the $2,500 saved — so 0% wins here.
More examples to test
- Conservative case: use a higher interest rate and lower growth assumptions to stress-test affordability.
- Optimistic case: use a lower rate with stable income assumptions to compare upside potential.
How to interpret results
Treat this as a planning model, not a final approval tool. Compare at least two scenarios and focus on total-cost and cash-flow trade-offs.
When this can be inaccurate
Results can diverge due to fees, changing rates, tax rules, lender policies, and behavior changes that simplified models cannot fully capture.
Change history
- July 2026: Quality-reviewed for publication with formula checks and explanatory copy updates.
Site-wide corrections also appear on the corrections log.
Compare top personal finance offers
Offers and rates vary by eligibility.
Frequently asked questions
Is cash back or low interest better?+
It depends on the loan amount, the rate gap, and the term. Long terms and big rate gaps favor low interest; small loans often favor the rebate.
Can I take cash back and finance elsewhere?+
Sometimes. If you can get a cheap loan from a bank or credit union, taking the rebate and financing separately can beat the dealer's low-rate offer.
Does credit score matter?+
Yes. Promotional 0% rates usually require excellent credit; without it, the cash-back path may be the only realistic option.
How should I use this result?+
Treat it as a planning estimate. Compare at least two realistic scenarios, then confirm with statements, quotes, or a qualified professional before acting.
How often should I refresh assumptions?+
Refresh whenever rates, income, costs, or policy limits change materially, and before making irreversible commitments.