[header] How to calculate a lease payment [title] Learn the three main components of a lease payment. [step] The first is depreciation, the reduction in the value of the car over the term of the lease. The second is financing, the amount that you pay for the use of the car. 
It is computed on the amount the leasing company invested to purchase it. The third is sales tax, which is added to the monthly lease payment in many u.s.