Auto guide
How is a lease payment calculated?
Three numbers produce a lease payment, and the dealer controls all three. Here is the formula, how to convert a money factor into a rate, and why rolling negative equity into a lease costs more than the amount you rolled in.
A lease payment looks opaque and is not. It comes from three numbers and a simple formula, and once you can reproduce the payment yourself you can tell immediately which number a dealer has moved.
The three numbers
Capitalized cost. The negotiated price of the car, plus anything rolled in — fees, taxes depending on your state, negative equity from a trade — minus your down payment (a "cap cost reduction") and any rebates.
Residual value. What the leasing company says the car will be worth at the end. Usually expressed as a percentage of MSRP and set by the finance company, not the dealer.
Money factor. The financing rate, quoted as a small decimal. Multiply it by 2,400 to get the approximate APR. A money factor of 0.00275 is about 6.6%.
The formula
The payment is two pieces added together:
Depreciation charge = (capitalized cost − residual) ÷ number of months
Rent charge = (capitalized cost + residual) × money factor
Note the second one carefully: the rent charge is calculated on the cap cost plus the residual, not the difference. That is how lease interest works, and it is why the money factor affects the payment more than people expect.
Worked example — a $40,000 car, residual $22,000, 36 months, money factor 0.00275:
- Depreciation: (40,000 − 22,000) ÷ 36 = $500
- Rent: (40,000 + 22,000) × 0.00275 = $170.50
- Payment before tax: $670.50
The lease payment calculator builds the payment this way, so you can see which half of it each change moves.
Why negative equity is worse on a lease
This is the part that catches people, and it is a direct consequence of the formula above.
Roll $5,000 of negative equity from a trade into a lease and the capitalized cost rises by $5,000. Now look at what that does:
- Depreciation charge rises by $5,000 ÷ 36 = $139 a month
- Rent charge rises by $5,000 × 0.00275 = $13.75 a month
That is about $153 a month, or $5,495 over the term, for $5,000 of rolled-in debt. The residual does not move — the car is not worth more because you owed money on the last one — so the entire $5,000 lands on the depreciation side, and it picks up a rent charge on top.
Which numbers are actually negotiable
- Capitalized cost — yes, and this is the main lever. Negotiate the price of the car exactly as you would for a purchase, before discussing monthly payments.
- Money factor — often yes, within limits. Dealers can mark it up over the finance company's buy rate. Ask what the buy rate is.
- Residual — no. Set by the finance company. A high residual is good for you and is one reason some cars lease far better than others.
- Fees — sometimes. The acquisition fee is usually fixed; documentation fees vary.
The tactic to avoid: negotiating on the monthly payment. A dealer can hit almost any payment target by extending the term, cutting the mileage allowance or raising the money factor. Agree the cap cost first, then ask for the money factor, then check the payment against the formula.
Two more things that move the real cost
The mileage allowance. A lower allowance lowers the payment by raising the residual, and then charges you per mile at the end. Be honest about your annual mileage — it is much cheaper to buy the miles up front than at turn-in.
Money down. A cap cost reduction lowers the payment, but if the car is written off early the money is generally gone — you have prepaid depreciation on a car you no longer have. Many people put less down on a lease than on a purchase for exactly this reason.
What to ask
- What is the money factor, and what is the buy rate? Then multiply by 2,400.
- What is the residual, in dollars and as a percentage of MSRP?
- What is the agreed capitalized cost, itemized — and what exactly has been rolled into it?
- What is due at signing, and what does that consist of?
- What is the mileage allowance and the overage rate?
Reproduce the payment from those numbers yourself. If it does not match, one of the figures you were given is not the one being used.
Sources: the lease payment formula, the money-factor-to-APR conversion and the negative-equity figures are computed with this site's own model, on a $40,000 car with a $22,000 residual over 36 months at a money factor of 0.00275 — the same arithmetic the calculator runs.