Your New Car - Buy or Lease? How Do You Decide?

As an attorney, I often find myself advising clients on many things: real estate, borrowing money, business issues, wills, and even advice about buying a new car. I have a background in economics and finance and clients ask me to help them analyze their car lease and direct them towards making a more informed decision. Since both leases on our cars are coming due, I thought it a good time to share how I do these analyses.


First of all, you should know that the automotive industry uses their own math when it comes to money. This seems somewhat obvious since we all know that the car companies make more money financing cars than they do selling them. Here is a very simple example: when calculating interest on a car loan, dealerships use a method called "add-on interest." Simply put, they add on the interest to the price of the car and divide by the term of the loan. So, if you are buying a $35,000 car and taking a 60-month loan from the dealership at 4% interest, they simply calculated the annual interest (35,000 x .04 = 1,400). Then they multiply the annual interest payment by 5 years (1,400 x 5 = 7,000) and add it to the price of the car (35,000 + 7,000 = 42,000). To determine the monthly payment, the final figure is then divided by the term of the loan (42,000 / 60 = 700.00). Now you know why leasing became so popular! So, why is this "add-on interest" method incorrect? Because you are paying interest on the loan as if the entire balance was outstanding for the entire duration of the loan. If you obtained a loan from your local bank, the loan would be "amortized" meaning you would only pay interest on the then outstanding balance. That is the case with an amortized mortgage loan and if you make extra payments, you will save interest as the loan balance decreases.


This "add-on" method is not just loan calculation for dummies so the dealership can easily calculate your payment (we know all those dealership finance guys are a lot smarter than that!!). It allows the car companies and dealerships to quote a lower rate of interest. Let's take the 4% example from above. If we use a loan amortizing calculator, we can determine the actual interest rate on a $35,000 loan repaid over a 60 month period. It's 6.2% which is probably closer to a local bank rate and is 55% higher than the rate quoted!


Another "game" the car companies have been playing is "zero interest" financing. When this first came out, I had to ask myself: how can the manufacturers sell these cars for 0% especially given the fact that we know they make more money financing cars then selling them? Then I started to notice a common thread. Almost all offers I have seen give you an alternative: zero percent financing or cash back on the purchase. In other words, if you choose to buy the car for cash (or finance through another independent source), the manufacturer is willing to forego a certain amount of cash. Therefore, the cash back incentive is really just added on interest! To illustrate, let's assume for our $35,000 new car, our choice is zero percent financing for 60 months or $3,000 cash back. Calculating the monthly payment is easy (even easier than add on interest!). You just divide the purchase price by the term of the loan (35,000 / 60 = 583.33). To calculate the "true" interest rate, you use your amortizing calculator with a present value sum of $32,000 (35,000 purchase price less the cash back amount of 3,000). The true interest rate is 3%. Still not bad, but not zero percent. (Note: there are some "true" zero deals out there, but they are very hard to come by).


So now you know a little bit about buying which hopefully will help you with your next purchase. Now, what about leasing? Leasing is actually the process of "renting" the car from a third party purchaser. Even if you lease through the manufacturer, their leasing division is actually buying the car from the dealership and then rents or leases it back to you. Calculating lease payments are complicated and you need a few factors to make your own analysis: total capital cost, residual value (or percentage) and money rate. If you'd like to figure it out for yourself, there are plenty of lease calculators floating around the net. But that won't help you much because you are using their math, not your own. Let me show you how I calculate payments and analyze lease deals using my math.


First, one rule I try to follow: avoid putting money down on a lease. If possible, roll taxes, inception fees, dmv charges, etc. . . into the payment. And NEVER put additional money down to reduce your monthly payment. What you are doing is giving money upfront to the leasing company to reduce your rental payment. If you drive off the lot and a tractor trailer totals your vehicle (assuming you are completely unharmed - always a good starting point when using accident examples!), you will not get your down payment refunded, nor taxes returned, etc... You'd be much better off taking the down payment, putting it in a bank account and using it to offset your monthly payment. For downpayments, rule of thumb is that the payment will decrease by about $25 per month for every $1,000 you put down to reduce the cost of the car.


So, how to analyze the lease payment. Look at it this way: you are actually renting part of the car (the residual amount) and purchasing the balance. Meaning you are (in the leasing company's eyes) using up a certain amount of the car. This is their biggest gamble. If they charge you for using up 45% of the car and it turns out that the fair market value of the residual is actually much lower than 55% at the end of the lease, they lose money on the deal. That is why you might have heard that many of the American manufacturers are leaving the leasing business when it comes to the large SUVs. Due to the economy and gas prices, they just are not holding their value as the leasing companies had expected.

Back to payment analysis...


So you need to make two payment calcs and add them together. First, take the residual value and calculate an interest-only payment. Using our above residual factor of 55%, the residual value is determined by multiplying the total capital cost of the vehicle by the residual factor ($35,000 x .55 = 19,250). Here's where you can get a little creative. You choose the interest rate - yes you heard me - you choose the rate. Meaning, you decide at a given interest rate what you are willing to pay and can play around with the formula from there. Let's use 4%, so the interest-only portion of the monthly payment is calculated by multiplying the residual value by the chosen interest rate then dividing by twelve to obtaining a monthly figure (19,205 x .04 = 770 / 12 = 64.17). The theory behind this is you only need to pay interest because this "portion" of the car you are actually giving back to the leasing company at the end of the lease. Therefore, they should only be looking for interest on their money. Second, you need to calculate an amortized payment on the amount of the car you are "using up." This figure is determined by subtracting the residual value from the total capital cost of the car including all fees, charges, taxes, etc... (35,000 - 19,250 = 15,750). Using your amortizing calculator, you can amortize the payments of a loan for 15,750 at 4% over a 60-month period. The resulting figure is 262.77. Add your two monthly figures together to determine the monthly lease payment (64.17 + 262.77 = 326.94). You can also use this logic to analyze whether a proposed lease payment is reasonable. Just ask the dealer for the total capital cost of the car and the residual value or percentage. You should be able to back into the rest.

I welcome comments and questions.