Bond Repayment Calculator

How the Bond Repayment Calculator Works

A home loan amortisation schedule shows exactly how each monthly payment is split between interest and principal repayment, and what the outstanding balance is at the end of each period. In the early years of a bond, the vast majority of each payment goes toward interest - principal repayment accelerates only as the balance reduces and the interest component shrinks.

For example, on a R1.5 million bond at 10.25% over 20 years, the monthly repayment is approximately R14 700. In month one, roughly R12 800 of that is interest and only R1 900 reduces the principal. By year 15, the split has reversed significantly - closer to R5 900 interest and R8 800 principal.

This slow initial paydown is why the outstanding balance on a home loan reduces so slowly in the early years - a common surprise for first-time homeowners who expect to build equity faster. The amortisation table makes this visible year by year.

The table is also useful for tax purposes if you own a rental property: the interest portion of each payment may be deductible against rental income. The schedule shows the annual interest paid in each tax year, which your accountant will need for the ITR12 return.

How to Use This Calculator

1. 1

   Enter your bond amount

   Use the total loan amount approved by your bank - the purchase price less any deposit paid. If you are checking an existing bond, use the current outstanding balance from your latest statement.

2. 2

   Set the interest rate

   Enter the annual interest rate on your home loan. If you have a variable-rate bond (the default in South Africa), this changes when the prime rate changes. Use your current rate for an accurate schedule, or model a stress test at prime plus 2% to see the impact of rate increases.

3. 3

   Set the remaining term

   For a new bond, use the full loan term (typically 20 years). For an existing bond, use the remaining months - found on your latest home loan statement or by calling your bank.

4. 4

   Expand the amortisation schedule

   Toggle the year-by-year breakdown to see the annual interest paid, principal repaid, and outstanding balance at the end of each year. This is useful for financial planning, tax calculations on rental properties, and understanding your equity build-up.

Frequently Asked Questions

Why does my bond balance reduce so slowly at first?

This is a natural feature of amortisation. In the early months, the outstanding balance is at its maximum, so the monthly interest charge is highest. Most of each payment covers this interest, leaving little to reduce the principal. As you pay down the balance over years, interest charges fall and more of each payment goes to principal - accelerating the paydown in the later years of the loan.

How do I calculate my home equity in South Africa?

Home equity is the current market value of your property minus the outstanding bond balance. For example, if your property is worth R2 million and your outstanding bond balance is R1.3 million, your equity is R700 000. Equity builds as: (1) the bond balance reduces through repayments, and (2) the property value increases over time. You can access this equity through a further loan (home equity loan) or by selling.

Can I see the interest I paid for tax purposes?

Yes - the amortisation schedule shows the interest paid in each year. If your property is a rental property, the interest portion of your bond repayment is deductible against rental income for tax purposes. Keep your bond statements for each tax year, or use the schedule as a guide. Your bank will also issue a certificate of interest paid on request, which is the authoritative document for SARS.

What is the difference between a repayment bond and an interest-only loan?

A standard repayment bond (the most common in South Africa) requires monthly payments that cover both interest and a portion of principal, so the balance reduces each month and reaches zero at the end of the term. An interest-only loan requires only the monthly interest - the balance never reduces and must be repaid in full at the end. Interest-only structures are rare in South African residential lending but more common in commercial property finance.

How does a rate change affect my bond schedule?

When the prime rate changes, your variable-rate bond's interest rate changes by the same amount. If you keep the same monthly instalment, the term effectively shortens (when rates fall) or lengthens (when rates rise). If you ask the bank to adjust the instalment to match the new rate, the term stays constant. Most South African banks automatically adjust the instalment when rates change unless you request otherwise.