Vehicle EconomicsAuto Loan Fees Impact Calculator
See the full financed lifetime cost of rolling a fee into your loan instead of paying it in cash.
Why this comes up
Dealer document fees, title fees, and add-on charges are usually small enough that they get waved off as "just roll it into the loan." That framing hides the real cost: a fee financed alongside the rest of the loan accrues interest at the loan's own rate for the entire remaining term, not a one-time charge.
How we calculated this
We amortize the loan twice at the same APR and term, once without the fee and once with it added to principal. The difference in total interest between the two is the fee's financed interest cost, on top of the fee itself.
Worked example, using this page's own defaults ($25,000 loan, $800 fee, 6% APR, 60 months): financing the fee adds a modest amount to the payment and a real chunk of interest on top of the $800 face value. Run the calculator above to check your own numbers.
What this means
- A small fee is effectively financed at your full loan APR for the whole remaining term, not a one-time charge, that's the real reason to pay it in cash if you can.
- If paying the fee in cash competes with a larger down payment for the same cash, compare both options directly with Larger Down Payment vs Keep Cash.
- A high APR or long remaining term makes financing a fee meaningfully more expensive than the same fee on a short, low-rate loan.
Limitations
This does not assert that any specific fee is legitimate or avoidable, only what it costs if financed versus paid in cash. See Methodology.
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.