Loan Repayment Calculator

How This Calculator Works

This calculator uses the standard amortisation formula to break down any loan into equal monthly instalments, showing you exactly what you will pay each month over your chosen term. You enter the principal amount in ZAR, the annual interest rate, and the repayment period in months. The calculator applies the formula M = P[r(1+r)^n] divided by [(1+r)^n minus 1], where P is the principal, r is the monthly interest rate, and n is the number of instalments. The result shows your fixed monthly instalment, the total amount repaid over the full term, and the total interest cost. In South African terms, this total cost of credit is a figure lenders are legally required to disclose under the National Credit Act. Understanding this figure helps you compare loan offers accurately, spot whether a lender's quoted instalment matches what the formula predicts, and budget responsibly before signing any credit agreement. The calculator works for personal loans, vehicle finance, home loans, and any other amortising credit product.

What Affects Your Repayment

• The principal amount directly determines your instalment size: a larger loan means a higher monthly payment and significantly more interest paid over the full term.
• The annual interest rate has a compounding effect on total cost. Even a one or two percentage point difference can add thousands of rands to the total amount repaid.
• The repayment term stretches or compresses your instalments. A longer term lowers your monthly payment but increases the total interest you pay, sometimes dramatically.
• The initiation fee, which the NCA caps for most credit products, is typically added to the principal or charged upfront, affecting your effective borrowing cost from day one.
• The monthly service fee charged by the lender adds a fixed rand amount to every instalment. These fees must be disclosed in your pre-agreement quote and are part of the total cost of credit.
• Credit life insurance premiums, often bundled into loan agreements, increase your monthly instalment and the overall cost, so it is worth checking whether your existing cover qualifies as a substitute.
• Early settlement or additional payments reduce the outstanding principal faster, cutting the total interest owed, although some lenders apply an early settlement fee permitted under the NCA.

Tips to Lower Your Repayment

• ✓Always compare the total cost of credit, not just the monthly instalment. A lower instalment spread over a longer term can cost far more in interest than a shorter, higher-payment option.
• ✓Use this calculator before applying so you know your expected instalment. If a lender's quoted figure differs significantly, ask them to explain the full cost breakdown in writing.
• ✓Check whether your lender uses DebiCheck for debit order authentication. DebiCheck mandates are more secure and reduce the risk of disputed deductions from your account each month.
• ✓Under the NCA, you are entitled to a free pre-agreement statement and quotation that holds the interest rate firm for five business days. Use this window to run the numbers here and compare offers.
• ✓Keep your loan term as short as your budget allows. Reducing the term by even six months can save a meaningful amount of interest on larger loans.
• ✓If you are consolidating multiple debts into one loan, input each existing loan separately to calculate your current total monthly outgo, then compare it against the consolidation instalment the calculator produces.
• ✓Remember that your instalment is only one part of responsible borrowing. The NCR requires lenders to perform affordability assessments, but you should also run your own budget check using your net monthly income against all committed expenses.

Frequently Asked Questions