How Car Lease vs Buy Calculator Works
The Car Lease vs Buy Calculator reveals the true total cost of each option over your intended ownership period so you can make a financially informed decision rather than relying on monthly payment comparisons alone. A lower lease payment doesn't always mean a cheaper path—and buying isn't always better either. This tool accounts for all the costs most people forget.
For the buy scenario, the calculator factors in the purchase price, sales tax, down payment, loan interest over the full term, maintenance costs (which increase as the car ages), insurance premiums, depreciation (using model-specific curves when available), and the estimated resale or trade-in value at the end of your holding period. It also includes the opportunity cost of your down payment—what that money could have earned if invested instead.
For the lease scenario, it accounts for the monthly payment, down payment (cap cost reduction), security deposit, acquisition fee, disposition fee, excess mileage charges based on your driving habits, wear-and-tear estimates, and the option to buy at lease-end residual value. It models multiple consecutive leases if your comparison period exceeds a single lease term.
The tool then calculates a total cost-of-ownership for each path and shows you the breakeven point—the month at which buying becomes cheaper than serial leasing (if it does). Use the Mortgage Refinance Break-Even Analyzer for similar breakeven logic on your home, or pair this with the Job Offer Comparison Calculator tool when a new job changes your commute distance and driving needs.
Key Terms Explained
- Residual Value
- The predicted value of the car at lease end, set by the leasing company, which determines your monthly payment and buyout price.
- Money Factor
- The lease equivalent of an interest rate, expressed as a small decimal. Multiply by 2,400 to convert to an approximate APR.
- Cap Cost Reduction
- The down payment on a lease that reduces the capitalized cost and lowers monthly payments.
- Disposition Fee
- A fee charged by the leasing company (typically $300-$500) when you return the vehicle at lease end.
- Opportunity Cost
- The potential investment returns you forgo by tying up cash in a vehicle down payment instead of investing it.
- Total Cost of Ownership
- The complete financial picture including purchase price, financing, insurance, maintenance, depreciation, and fees over the holding period.
Who Needs This Tool
Deciding whether to lease a new minivan or buy a certified pre-owned one given their 5-year planning horizon.
Evaluating lease vs purchase for a company vehicle considering tax deduction differences under Section 179.
Checking whether excess mileage penalties make leasing prohibitively expensive for their 20,000-mile-per-year driving.
Comparing the cost of leasing a new model every 3 years versus buying and holding for 7-10 years.
Understanding total costs when they can afford the lease payment but not the loan payment on the same car.
Methodology & Formulas
Buy total cost = Purchase Price + Sales Tax + Loan Interest - Resale Value + Maintenance + Insurance + Opportunity Cost of Down Payment. Lease total cost = (Monthly Payment × Months) + Down Payment + Fees + Estimated Excess Mileage Charges + Disposition Fee - Security Deposit Return. Opportunity cost uses a configurable annual return rate (default 7%) applied to the buy-scenario down payment. Depreciation follows an exponential decay model averaging 20% in year one and 15% annually thereafter unless overridden. Breakeven month is where cumulative buy cost drops below cumulative lease cost.
Pro Tips
- Always compare over the same time horizon—use at least 6 years to capture the long-term advantage of buying and holding.
- Include your actual annual mileage honestly in the lease scenario; excess mileage fees of $0.25-$0.30/mile add up fast.
- Factor in the opportunity cost of a large down payment—$10,000 invested at 7% becomes $14,000 in 5 years.
- If you drive less than 10,000 miles per year and prefer new cars every 3 years, leasing often wins on pure cost.
- Don't ignore maintenance: buying wins long-term only if you keep the car well past the point where repair costs rise.