How it works
A subprime auto loan is financing priced for elevated default risk — conventionally anything above roughly 10% APR, with deep-subprime contracts reaching the usury ceiling. The rate arrives framed as a monthly payment, which is precisely how its cost disappears: $496 a month sounds survivable, so nobody multiplies it out. This calculator does the multiplying. It finances the car at both the offered subprime rate and the rate a good-credit borrower would command, then reports the lifetime interest gap, the monthly gap, and the extra interest measured against the car's own price — the wake-up metric. On the defaults, $22,000 financed for 72 months at 17.5% accrues about $13,700 of interest versus $4,600 at 6.5%: an extra $9,000, equal to 38% of the vehicle's price, spent on nothing visible. The structural trap compounds — underwater from day one, such loans invite rollovers into the next subprime deal, converting one expensive car into a chain of them. The constructive exits are equally concrete: enlarge the down payment, shorten the term, buy less car, or defer twelve months while payment history rebuilds the score. And once refinancing becomes available, the same arithmetic runs in reverse, recovering thousands.
Formula
Extra interest = [payment(price−down, subRate, n) − payment(price−down, primeRate, n)] × n
Tips
- Read the 'total of payments' box on the contract before signing anything.
- Every $1,000 added to the down payment saves roughly $400+ in subprime interest.
- Shorten the term before lowering the payment — 48 months halves the bleed.
- Twelve on-time payments usually unlock refinance offers; calendar the check.
- Decline the payment-seller framing: always ask for rate, term and price separately.
Frequently asked questions
- How much more does a subprime auto loan really cost?
- Dramatically more. Financing $22,000 for 72 months at 17.5% versus 6.5% produces about $13,700 of interest versus $4,600 — an extra $9,000, roughly 38% of the car's price. Even a moderate 12.9% subprime rate still adds over $3,600 to the same transaction.
- What credit score counts as subprime for auto loans?
- Lenders commonly bucket scores below 620 as nonprime-to-subprime, with deep subprime under 580 commanding the harshest pricing — often 15–21% APR in recent markets. Prime pricing generally starts near 660–680, where rates fall into single digits. The tiers matter because each boundary crossed reprices the entire loan.
- Can I refinance a subprime car loan later?
- Yes, and it is the main escape hatch. After roughly twelve months of on-time payments, improved scores frequently qualify for rates several points lower. Refinancing that $22,000 balance from 17.5% to 8% with 54 months left cuts the payment by about $130 and saves thousands in remaining interest.
- Why is the payment gap smaller than the interest gap?
- Because the term stretches. Subprime contracts often extend to 72–84 months to compress the higher rate into a survivable monthly figure, so the payment rises only moderately while total interest balloons. The $126 monthly gap on our example conceals $9,000 of additional lifetime cost — the exact sleight the payment framing performs.
- Is it smarter to wait and save a bigger down payment?
- Often, yes. Each $1,000 of down payment removes financing entirely on that slice — at 17.5% over 72 months, roughly $480 of saved interest per thousand. Deferring purchase six to twelve months while rebuilding credit attacks both variables at once: smaller principal and a materially lower rate.