What Dealers Don't Want You to Calculate

Dealers in the U.S. make more when you don't run the numbers—OTD, total interest, trade value, and total cost of ownership. Here's what they don't want you to calculate and why you should do it anyway.

TL;DR Calculate: (1) out-the-door price, (2) total interest over the life of the loan, (3) your trade-in value, (4) total cost of ownership. When you have those numbers, you don't overpay on price, interest, or trade—and you don't buy a car that's expensive to own. Use autopremo.com for OTD, payment, trade-in, and ownership cost.

1. Out-the-Door Price (OTD)

What it is: Selling price + tax + all fees. The real number you pay for the car. Why dealers don't want you to focus on it: They prefer you focus on "monthly payment" or "price" (before fees). When you focus on payment, they can stretch the term or add fees. When you focus on "price" without fees, you miss doc fees, add-ons, and other line items that inflate the total. What to do: Negotiate and compare OTD only. Get the full breakdown in writing (selling price, incentives, fees, OTD). Use autopremo.com OTD calculator to know your target OTD before you go. Get your target OTD at autopremo.com.

2. Total Interest Over the Life of the Loan

What it is: Total interest you'll pay from first payment to last. Depends on principal, rate, and term. Why dealers don't want you to focus on it: They make money on financing (kickbacks from lenders). They may push a longer term to "lower" your payment—which raises total interest. If you don't calculate total interest, you don't see how much you're paying in interest over 72 or 84 months. What to do: Use a payment/amortization calculator. Plug in OTD (minus down payment), rate, and term. See total interest. Use autopremo.com payment calculator. Compare 60 vs 72 vs 84 months at the same rate—and at different rates. Choose the combination that minimizes total cost (OTD + interest). Don't choose a term just to "hit" a payment. See total interest at autopremo.com.

3. Your Trade-In Value

What it is: What your current car is worth—trade-in value (what dealers pay) or private-party value (what you might get selling yourself). Why dealers don't want you to know it: If you don't know your trade's value, they can lowball you. They can say "we'll give you $7,000 for your trade" when it's worth $9,500—and you might accept because you haven't checked. Or they mix trade and purchase so you can't see that they're underpaying on the trade and overcharging on the new car. What to do: Get trade-in quotes from multiple sources (Carvana, KBB, Autopremo, etc.) before you go. Use autopremo.com trade-in tool. Negotiate purchase price (OTD) first, then trade separately. Compare their trade offer to your research. If it's low, push back or sell privately. Get your trade value at autopremo.com.

4. Total Cost of Ownership

What it is: Purchase/loan cost + depreciation + fuel + insurance + maintenance/repairs + fees over the time you own the car. Why dealers don't want you to focus on it: They want you to focus on "price" or "payment"—not on what the car will cost over 5 years. A car with a "low" payment can have high insurance, poor fuel economy, or high maintenance—so total cost is high. If you don't calculate it, you might buy a car that's expensive to own. What to do: Use a total-cost-of-ownership tool. Plug in purchase price, financing, fuel, insurance, maintenance, and depreciation. Use autopremo.com ownership cost tool. Compare cars by total cost—not just payment or sticker. Choose the car that fits your budget over the long run. See total cost of ownership at autopremo.com.

Your Calculation Checklist

• [ ] OTD (selling price + tax + fees) calculated and compared to market—use autopremo.com
• [ ] Total interest over life of loan calculated at different terms and rates—use autopremo.com payment calculator
• [ ] Trade-in value researched (multiple sources)—use autopremo.com trade-in tool
• [ ] Total cost of ownership estimated for cars you're considering—use autopremo.com ownership cost tool
• [ ] Negotiate and decide using these numbers—not just payment or sticker

Get all your numbers at autopremo.com.

Bottom Line

Dealers don't want you to calculate OTD, total interest, trade value, and total cost of ownership—because when you do, you don't overpay. Calculate all four. Use autopremo.com for OTD, payment, trade-in, and ownership cost—then negotiate and decide from fact, not feeling.