Lease vs buy calculator.

How the math works

The buy side uses the standard amortization formula on the financed amount (purchase price minus down payment): M = P × r / (1 − (1 + r)^−n), where r is the monthly rate (APR ÷ 12) and n is the term in months. Equity at any checkpoint is the cumulative principal paid down through that month, derived from the closed-form balance equation rather than walking the schedule. Equity at term end is principal paid plus the residual value you enter.

The leaseside uses weekly settlement × term-in-weeks for total payments. Equity build is $0 unless the contract specifies a completion bonus — most don’t. The monthly equivalent divides total payments by term-in-weeks ÷ 4.33 so the side-by-side cash flow is comparable.

The headline output is failure-adjusted cost. The trucking industry has documented an 80%+ wash-out rate on lease-purchase programs. The model assigns 80% probability to the failure case (operator exits at roughly the midpoint of the term with $0 recovered) and 20% to the completion case (operator pays the full schedule and receives the stated completion equity). The expected-value cost is the weighted average of those two outcomes — and it’s consistently lower than the everyone-completes case the lease brochure is sold on.

• What is modeled — payment math, equity build, residual, expected-value cost under the documented failure rate.
• What is NOT modeled— insurance, fuel, maintenance differences (some lease programs bundle these, others don’t), tax treatment, financing fees, prepayment penalties, dispatch-related deductions, and force-majeure exit terms. Read the contract.

Lease-purchase: the failure rate problem

Industry estimates of lease-purchase wash-out rates run from roughly 80% to as high as 96% depending on the carrier, the vintage of the program, and how strictly “completion” is measured. The drivers are well-documented: weekly settlements that don’t survive a slow week, maintenance and breakdown costs that aren’t included in the lease quote, and contract language that treats any missed payment as a forfeiture rather than a deferral. The operator walks, the truck goes back into the program, and the next driver starts the cycle at week one.

The math the calculator shows isn’t a prediction for any individual operator — it’s an expected-value estimate across the population the program enrolls. Most first-time owner-operators evaluating a lease-purchase offer are looking at the optimistic case (complete the term, take the truck, own a paid-off Class 8). The failure-adjusted line is what the same offer looks like when the base rate is applied honestly.

When lease-purchase actually makes sense

Lease-purchase isn’t universally wrong. It can be a defensible path when (1) the operator has no credit and no path to equipment financing in the next 12–24 months, and the alternative is staying a company driver indefinitely; (2) the carrier’s program is genuinely structured for completion — fixed weekly deduction with no hidden maintenance escrow, transparent equity-accrual schedule, and a documented completion rate above 30% (ask for it in writing); and (3) the operator has 3+ months of personal reserves so a slow week doesn’t force the exit. Outside those conditions, equipment financing on a used truck — even a higher-mileage one — is almost always the better trade.

Limitations and disclaimers

This calculator is a comparison aid, not a recommendation and not an underwriting decision. The APR you enter on the buy side is a user-supplied estimate — the actual APR is set by the chosen lender on the term sheet (see methodology for observed panel ranges). The lease side assumes the contract behaves linearly between today and the equity-payout date, which is rarely how lease-purchase contracts read. Real contracts vary widely on maintenance escrows, fuel surcharges, dispatch-related deductions, and what counts as “completion.” Read the contract. Have it reviewed. Run the calculator a second time with the worst-case weekly deduction the contract permits.