Vehicle Economics60 vs 72 Month Auto Loan
The shorter term always costs less interest. The question is whether the payment relief is worth it.
Why this comes up
Dealers quote 72 months almost by default now, because it produces the smallest monthly number on the sheet. That number is real, but it is only half the decision. Stretching the same loan from 60 to 72 months does not just lower the payment, it changes how much interest you pay and how long you are financing a vehicle that is losing value the whole time. Most buyers never see the interest side of that tradeoff laid out next to the payment side, which is exactly what this engine exists to show.
How we calculated this
Each term uses the standard fixed-rate amortization formula, payment equalsP × r / (1 − (1 + r)⁻ⁿ), where P is the loan amount,r is the monthly rate (APR ÷ 1200), and n is the number of months. We run a full monthly schedule for both terms at the same APR and sum the interest column for each.
Worked example, using this page's own defaults ($25,000 at 6.5% APR): the 60-month payment comes out to $489.15 with $4,349 in total interest; the 72-month payment comes out to $420.25 with$5,258 in total interest. Stretching six years costs $68.91 less per month and $909 more overall, run the calculator above to check that against your own numbers.
What this means
- The interest gap between terms grows faster at a higher APR: a subprime rate makes the 72-month choice materially more expensive than a prime rate does, even on the identical loan amount.
- A lower payment does not lower your negative-equity risk, it usually raises it, because you are financing longer while the vehicle keeps depreciating on the same schedule regardless of your loan term.
- If cash flow is genuinely tight, the 72-month payment is a legitimate choice, just make it deliberately, as a cash-flow decision, not because it looked like the loan "cost less."
- Some lenders price longer terms at a higher rate than shorter ones. Confirm your actual quoted APR for each term before comparing, this calculator assumes the same rate for both.
Limitations
This is a planning model, not a payoff quote. It assumes the same APR at both terms, which is not always what a lender will actually offer, and it does not model prepayment penalties, GAP insurance, or a lender's specific daily-interest accrual method. See Methodology for what this fixed-rate amortization model does and does not account for.
Methodology
This engine is built on Vehicle Economics' fixed-rate amortization model: the standard loan-payment formula run out as a full month-by-month schedule. See Methodology for the full detail.