Bond Repayment Calculator South Africa
Calculate your exact monthly repayment, total interest and how extra payments cut years off your bond.
Quick answer: A South African bond is repaid through amortising monthly instalments that blend interest and capital. At the current prime rate of 10.75% (SARB, 23 September 2026), a R1,500,000 bond over 20 years costs approximately R15,228 per month, with early years weighted mostly toward interest.
Bond Repayment Calculator
Prime: 10.75% · Investor rate: typically prime + 0.5% to prime + 1.5% (our estimate)
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How to Use This Calculator
- Purchase PriceEnter the total price of the property you are considering.
- DepositEnter the amount you plan to put down. The calculator works out your loan amount and deposit percentage automatically.
- Annual Interest Rate (%)Use 11.25% for prime plus 0.5% if you have a strong credit profile.
- Bond Term (years)Select your repayment term. Twenty years is standard for SA investment property bonds.
- Extra Amount Per MonthAdd any amount above the minimum repayment to see how much interest and time you save.
- Click Calculate Bond RepaymentThe results show your monthly repayment, total interest, and the minimum rental needed to cover your bond at different coverage ratios.
How Bond Repayments Work in South Africa
A South African home loan, called a bond, works on an amortising repayment structure. This means each monthly payment covers both interest and a portion of the original loan (the principal). In the early years, most of your repayment goes toward interest. As the loan balance decreases, the interest portion shrinks and the principal portion grows.
The formula used to calculate your monthly repayment is: M = P × [r(1+r)^n] ÷ [(1+r)^n − 1], where P is the loan amount, r is the monthly interest rate (annual rate divided by 12) and n is the number of monthly payments (years multiplied by 12). At the current prime rate of 10.75%, an investor paying prime plus 0.5% on a R1,500,000 bond over 20 years pays approximately R15,739 per month.
Why Extra Payments Are a Powerful Investor Strategy
Because SA bonds are front-loaded with interest, paying even a small extra amount each month has a disproportionate impact. Every rand of extra payment reduces your outstanding balance, which immediately reduces the interest charged the following month. This creates a compounding saving effect that accelerates over time.
On a R2,000,000 bond at 11.25% over 20 years, paying R1,500 extra per month saves approximately R711,000 in interest and cuts the term by almost 4 years. That freed-up equity can then be deployed as a deposit on a second investment property, creating a powerful property accumulation strategy without requiring additional income.
Most SA bond agreements allow extra payments into an access bond facility, meaning the money remains accessible in an emergency while still reducing your interest charge. Confirm this feature with your bank when signing your bond documents.
Bond Repayment Rates at 11.25% (Prime + 0.5%): Reference Table
| Loan Amount | 20 Years | 25 Years | Total Interest (20yr) |
|---|---|---|---|
| R 800,000 | R 8,394 | R 7,986 | R 1,215,000 |
| R 1,000,000 | R 10,493 | R 9,982 | R 1,518,000 |
| R 1,500,000 | R 15,739 | R 14,974 | R 2,277,000 |
| R 2,000,000 | R 20,985 | R 19,965 | R 3,036,000 |
| R 2,500,000 | R 26,231 | R 24,956 | R 3,796,000 |
| R 3,000,000 | R 31,478 | R 29,947 | R 4,555,000 |
Rates calculated at 11.25% per annum. Actual repayments depend on your negotiated rate and bond structure.
20-Year vs 25-Year Bond: Which is Better for SA Investors?
The standard term for SA investment property bonds is 20 years. Most property investors who have run the numbers choose 20 years for a straightforward reason: the additional monthly cost over a 25-year term is modest, but the interest saving over the life of the bond is enormous.
On a R2,000,000 bond at 11.00%, a 25-year term saves approximately R1,042 per month versus 20 years. But the 25-year term costs an extra R926,000 in total interest over the life of the loan. Most SA investors regard that as an expensive way to lower a monthly commitment, particularly when the property should be generating rental income to cover most of the repayment anyway.
The practical rule: choose 20 years and use an access bond facility as your buffer. If cash gets tight, temporarily reducing your extra payment achieves the same effect as a longer term without the lifetime interest cost.
The SA Bank Rental Coverage Test
When SA banks assess investor bond applications, they apply a rental coverage test: the expected monthly rental income must cover at least 100–110% of the bond repayment (our estimate). Some banks apply this as a standalone test; others fold it into the broader debt service ratio (DSR) assessment alongside your personal income.
The Investor Rental Offset panel in this calculator shows you the rental income required at 100%, 110%, and 125% coverage. A 125% coverage ratio means the property generates enough rental income to cover the bond repayment and have 25% left over for rates, levies, maintenance and vacancy. That is a useful threshold for identifying genuinely cash-positive investments at the current interest rate. Before committing, run your salary through PayTools to confirm your exact net monthly income, because bond serviceability is assessed on take-home pay, not gross salary. The Bond Affordability Calculator shows how much a bank would lend on your income.
Manual Calculation: Working Out Your Own Bond Repayment
The bond repayment formula is M = P × [r(1+r)ⁿ] ÷ [(1+r)ⁿ − 1], where P is the loan amount, r is the monthly interest rate, and n is the number of monthly payments. At the current prime rate of 10.75% (SARB, 23 September 2026), the monthly rate is 10.75% ÷ 12 = 0.896%. For a R1,500,000 bond over 20 years (240 months), this gives a monthly repayment of approximately R15,228. Extending the same bond to 25 years (300 months) drops the monthly repayment to roughly R14,431, saving R797 a month. Total interest paid rises from around R2.15 million to R2.83 million over the life of the loan, an extra R674,593 in interest for the lower monthly instalment. Investors weighing this trade-off should model both terms against expected rental income and their own cash flow tolerance before committing to a 25-year structure purely to lower the monthly repayment.
Working out your bond costs? See where this fits in the complete SA Home Buyer's Guide →
Frequently Asked Questions
South African bond repayments use the standard amortisation formula: M = P × [r(1+r)^n] ÷ [(1+r)^n − 1]. P is the loan amount (purchase price minus deposit), r is the monthly interest rate (annual rate ÷ 12) and n is the total number of months. At prime plus 0.5% (11.25%) over 20 years, a R1,500,000 bond costs approximately R15,739 per month.
The South African prime lending rate is 10.75% as of September 2026. In our estimate, investment property bonds are typically priced at prime plus 0.5% to prime plus 1.5% depending on your credit profile and deposit size, giving effective rates of 11.25% to 12.25%.
Yes, significantly. On a R1,500,000 bond at 11.25% over 20 years, paying just R1,000 extra per month saves approximately R488,700 in interest and cuts around 3.6 years off your term. The earlier you start extra payments, the greater the saving because interest is front-loaded in an amortising loan.
Most South African banks offer investment property bonds over 20 years as the standard term. Some will approve 25-year terms for owner-occupied purchases. A 20-year term is the norm for buy-to-let investors and results in higher monthly repayments but significantly less total interest than a 25-year term.
In our estimate, SA banks typically want rental income to cover at least 100–110% of the bond repayment. As a practical rule, your monthly rental income should exceed your bond repayment by enough to also cover rates, levies, maintenance and vacancy. A good SA investment property achieves 6–9% gross yield. Use this calculator alongside the Rental Yield Calculator to stress-test both numbers together.
For investment properties, a 20-year bond is strongly preferred by most SA property investors. The monthly repayment is higher, but total interest paid is dramatically less. On a R2,000,000 bond at 11.00%, a 20-year term costs approximately R926,000 less in total interest than a 25-year term, in exchange for a repayment about R1,042 a month higher. The shorter term also builds equity faster, improving your LTV for future investment purchases.
South African banks typically lend up to 30% of your gross monthly income toward bond repayments. On a R20,000 gross salary, maximum repayment is around R6,000/month, which qualifies you for roughly a R535,000–R575,000 bond at current prime rates. Use the Bond Affordability Calculator for your exact figure.
A 0.25% rate cut saves roughly R160–R170 per month on a R1 million bond over 20 years, or approximately R38,000–R40,000 in total interest over the full term. On a R2 million bond, the saving doubles.
At 10.75% prime over 20 years, a R1 million bond costs approximately R10,150/month and accumulates roughly R1.44 million in total interest. Paying an extra R1,500/month cuts the term to under 14 years and saves over R520,000 in interest.
South African home loans use a daily-balance reducing method. Every extra rand paid immediately reduces the outstanding balance, which reduces the interest charged the next day. Even modest extra payments of R500–R1,000 per month save hundreds of thousands over a 20-year term.