A car's sticker price is just the starting point. By the time you add state and city sales tax, factor in your trade-in, and choose a loan term, your actual monthly payment can look very different from the number the dealer quotes you. This guide walks through everything that goes into your payment — so nothing surprises you at the signing table.
What actually goes into your monthly car payment
Your monthly payment has four components:
- Principal repayment — paying back the amount you borrowed
- Interest — the cost of borrowing, based on your APR and loan balance
- Sales tax — typically rolled into the loan, not paid upfront (varies by state and city)
- Fees — documentation, title, registration fees (usually a few hundred dollars)
Most people focus on the monthly payment. The smarter move is to focus on the total cost — what you actually pay over the life of the loan, including all interest.
How sales tax varies by state and city
Sales tax on a car purchase is one of the most overlooked costs. It's usually financed into the loan, which means you're also paying interest on it for the full term.
| Location | Rate | Tax on $35K car |
|---|---|---|
| Oregon, Montana, NH | 0% | $0 |
| Virginia | 4.15% | $1,453 |
| Texas (state average) | 6.25% | $2,188 |
| California (LA) | 10.25% | $3,588 |
| Tennessee (Nashville) | 9.75% | $3,413 |
| Illinois (Chicago) | 10.25% | $3,588 |
| Washington (Seattle) | 10.35% | $3,623 |
How loan term affects what you actually pay
Stretching your loan to get a lower monthly payment is one of the most expensive mistakes car buyers make. Here's how the numbers look on a $30,000 loan at 6.5% APR:
| Term | Monthly payment | Total interest | Total cost |
|---|---|---|---|
| 36 months | $919 | $1,076 | $31,076 |
| 48 months | $710 | $1,445 | $31,445 |
| 60 months | $585 | $1,813 | $31,813 |
| 72 months | $503 | $2,208 | $32,208 |
| 84 months | $444 | $2,614 | $32,614 |
What's a good interest rate in 2026?
Auto loan rates in 2026 depend primarily on your credit score, the age of the vehicle, and where you borrow from:
| Credit score | New car rate | Used car rate |
|---|---|---|
| 720+ (Excellent) | 5.0–7.0% | 6.0–9.0% |
| 680–719 (Good) | 7.0–10.0% | 9.0–12.0% |
| 620–679 (Fair) | 10.0–14.0% | 12.0–16.0% |
| Below 620 (Poor) | 14.0–20%+ | 16.0–24%+ |
Credit unions consistently offer rates 1–2 percentage points lower than banks for the same credit profile. Getting pre-approved before visiting the dealer is one of the best moves you can make — it gives you a rate benchmark and removes the dealer's ability to mark up your financing.
Down payment: how much should you put down?
The standard recommendation is 20% down on a new car and 10% on a used car. Here's why it matters beyond just lowering your payment:
- New cars lose 15–20% of their value in the first year. A 20% down payment keeps you from going underwater immediately.
- A larger down payment reduces your loan-to-value ratio, which can unlock better interest rates.
- If the car is totaled, insurance pays market value — not what you owe. Equity protects you from owing the difference.
How the trade-in works
Trading in your current car reduces both the amount you need to finance and, in most states, the amount you pay sales tax on. The dealer's offer is usually below private sale value — check KBB or Edmunds first so you know what your car is worth before negotiating.
One common mistake: letting the dealer blur the trade-in into the purchase negotiation. Always negotiate the purchase price of your new car first, then negotiate the trade-in value separately. This prevents dealers from adjusting one to mask movement in the other.
Getting the best deal
- Get pre-approved by a credit union or bank before visiting the dealer
- Negotiate the out-the-door price, not just the monthly payment
- Get the trade-in offer separately, after agreeing on the purchase price
- Choose the shortest loan term your budget allows — 48 or 60 months
- Know your state and city's exact sales tax rate before you go in