When you're looking for auto financing, or already have it, interest rates play a much larger role than most people realize. From the monthly payment you make to the total cost of your vehicle over time, even a small rate change can have a noticeable effect.

Understanding how interest rate fluctuations impact auto loan payments is essential to making informed decisions, especially in an economy where rates can shift quickly. Here’s what to know before you sign a contract or consider refinancing:

What exactly is an interest rate?

Your interest rate is the percentage a lender charges you for borrowing the money to buy your vehicle. It’s a reflection of your credit score, the length of your finance term, your down payment, and broader market factors. The higher your rate, the more you pay in interest over time — and the slower you build equity in the vehicle.

The real impact of interest on monthly payments

A shift in rates can make a surprising difference in affordability, as evidenced in this $20,000, 60-month financing example:

• 9.5% interest rate: A monthly payment would be close to $420.04, with 5,202.23 in total interest paid

• 10.5% interest rate: A monthly payment would rise to about $429.88, and the total interest jumps to $5,792.68

• 11.5% interest rate: A monthly payment would climb to nearly $439.85, with $6,391.13 in interest.

These differences may seem small month-to-month, but they really add up over five years. That’s why timing matters. Securing financing when rates are low can save thousands.

What happens when rates rise?

If you’re shopping for a car while interest rates are increasing, you’ll likely face higher monthly payments unless you make adjustments, such as choosing a less expensive vehicle, increasing your down payment, or selecting a shorter finance term.

If you already have fixed-rate financing, your payments won’t change. But if you’re considering trading in your car for a new one, be cautious. Swapping into a higher-rate financing agreement could increase your monthly payment and the total you pay over time.

Is refinancing worth it?

Refinancing your auto financing could make sense if rates have dropped or your credit has improved significantly since you first borrowed. It may reduce your interest rate and monthly payment, but it’s not always the right move.

You’ll want to consider:

• Whether there are any fees involved

• How much longer you’ll extend the finance term

• If the new rate is meaningfully lower than your current one

Refinancing generally works best when you can keep the same or shorter term and avoid pushing more debt into the future.

When is it smarter to keep, refinance, or trade?

It’s usually better to keep your current car if your existing rate is lower than current market rates, you’re close to positive equity, and the vehicle is reliable. In this case, riding it out protects you from higher interest costs and faster depreciation.

Refinancing makes the most sense when your rate is high, and you can qualify for a significantly better one. But be cautious about extending your finance term too far, as this could reduce your payments while costing more in the long run.

Trading in your vehicle may be necessary if your needs have changed, but try to wait until you’ve built up positive equity. Otherwise, you could roll your old debt into new, higher-rate financing, putting you further behind financially.

Thinking about trading in your vehicle?

While Credit Acceptance doesn’t refinance vehicles, dealers in our network offer predictable, fixed-rate auto financing for your next car. We also have an incredibly large network of participating dealers, with over 15,000 nationwide. To see what monthly payment you may be approved for, get pre-qualified on our website today.