How this calculation works
For a fixed nominal annual rate r and n monthly repayments, the base instalment is P × (r/12) ÷ [1 − (1 + r/12)⁻ⁿ], using r as a decimal. The initiation fee is financed. Interest is rounded to cents each month; service fees and insurance are paid separately. The final payment settles rounding differences.
A worked example
A R12 000 loan at 0% over 12 months, without fees or insurance, needs R1 000 per month. Adding R200 each month settles it in 10 months.
Assumptions & limitations
- Fixed nominal annual interest, monthly interest periods and payments in arrears. Daily lender accrual may differ.
- All fees and insurance are user-supplied VAT-inclusive amounts, not regulatory fee limits or quotations.
- Extra payments are assumed accepted immediately without early settlement charges. Insurance is a fixed estimate, not a reducing-balance premium.

