Monthly payment (annuity):

1. Financed amount = Asset value − Advance payment
2. Monthly payment = K × (r × (1+r)ⁿ) ÷ ((1+r)ⁿ − 1)

• K — the financed amount
• r — the monthly interest rate (annual rate ÷ 12 ÷ 100)
• n — the term in months

Costs on top of the monthly payment:

• Arrangement fee — 2% of the financed amount, charged once
• Insurance — 100% of market value for a car, compulsory cover for property
• Registration and paperwork costs (vehicle registration and so on)

Worth keeping in mind:

• Rates are quoted as "from" figures — the rate you get depends on your financials.
• Payments follow an annuity schedule: the monthly amount stays flat while the interest share shrinks.
• The asset stays on the leasing company's books until the contract ends.