Bond Repayment Calculator
South Africa's most comprehensive bond calculator — simple payment, extended analysis, and professional simulator with full amortisation modelling
= R 140 000
Prime: 10.25%
Three levels of detail — pick yours
4 inputs, instant monthly repayment. Perfect for a quick sanity check on any property.
Affordability check, extra payments analysis, amortisation chart, and side-by-side scenario comparison.
Full month-by-month schedule, rate change modelling, lump sums, balloon payments, equity tracking, and tax analysis for investment properties.
Understanding Bond Repayments How to use • Formula • Example
How to Use This Calculator
Tier 1 — Simple Calculator (always visible)
Enter your Property price and a Deposit % (10% is typical). Select an interest rate — most South African banks lend at prime rate (10.25%) or prime+1% for standard home loans. Choose your Loan term (20 years is most common). Your monthly repayment appears instantly. Use the Share button to copy a shareable link.
Tier 2 — Extended Calculator
Open the Extended Calculator section below Tier 1 for four specialist tabs:
- Payment Analysis — adds insurance, bank fees, a payment composition chart, and a full year-by-year amortisation breakdown.
- Affordability Check — enter your income and expenses to find your maximum property price using SA banks' 30% DTI rule.
- Extra Payments — see exactly how many years you save and how much interest you avoid by paying extra each month.
- Compare Scenarios — put up to 3 scenarios side by side: different rates, terms, and deposits.
Tier 3 — Professional Simulator
For buyers, financial advisors, and accountants who need the full picture. Model future rate changes, annual lump sum injections, payment escalation, balloon payments, and investment property tax deductions. Generates a full month-by-month schedule with balance, equity, and LTV columns.
The Bond Repayment Formula
South African bonds use monthly compounding. The standard PMT (Payment) formula is:
Where:
- M = Monthly repayment
- P = Principal (loan amount = property price minus deposit)
- r = Monthly interest rate = Annual rate ÷ 12 ÷ 100
- n = Total number of monthly payments = Term in years × 12
For a R1,260,000 bond at 10.25% over 20 years:
r = 10.25% ÷ 12 ÷ 100 = 0.008542
n = 20 × 12 = 240
M = 1,260,000 × [0.008542 × (1.008542)²&sup4;°] ÷ [(1.008542)²&sup4;° − 1]
M ≈ R12,437 per month
Worked Example
Thabo is buying a R1,400,000 home in Johannesburg. He has saved a 10% deposit of R140,000, so he needs a bond of R1,260,000.
His bank approves him at the current prime lending rate of 10.25% on a 20-year term.
Using the PMT formula, his monthly bond repayment is R12,437.
Over 20 years, Thabo will pay a total of R2,984,880 — meaning he pays R1,724,880 in interest, which is 123% of the original purchase price.
If Thabo pays an extra R2,000 per month, he would pay off his bond in approximately 15 years and 4 months — saving over 4 years and 8 months and more than R450,000 in interest.
Frequently Asked Questions
What is the current prime lending rate in South Africa?
The current prime lending rate in South Africa is 10.25% (effective November 2025). The prime rate is set at the SARB repo rate plus 3.5 percentage points. The SARB's Monetary Policy Committee (MPC) meets every two months to review the repo rate.
Most South African home loans are granted at prime or prime + 1% (currently 11.25%). First-time buyers with strong credit profiles may qualify for sub-prime rates.
How much deposit do I need for a home loan in South Africa?
South African banks typically require a minimum deposit of 10% of the property value, though some lenders offer 100% bonds (no deposit required) to qualifying buyers with excellent credit.
A larger deposit has several advantages: it reduces your monthly repayment, lowers your total interest paid, and may secure you a better interest rate. A deposit of 20% or more is generally viewed very favourably by lenders. The FLISP (First Home Finance) government subsidy can also supplement your deposit if your household income is between R3,501 and R22,000 per month.
Is a 20-year or 30-year bond term better?
A 20-year term means higher monthly payments but significantly less total interest paid. A 30-year term offers lower monthly payments and greater cash flow flexibility, but you pay far more interest over the life of the loan.
For a R1,260,000 bond at 10.25%: a 20-year term costs roughly R12,437/month (total interest ~R1.72M), while a 30-year term costs about R11,166/month but total interest rises to approximately R2.76M. The 10-year extension costs an extra R1M in interest. Use the Compare Scenarios tab in the Extended Calculator above to model any combination.
Can I pay off my bond early without penalties in South Africa?
Under the National Credit Act (NCA), South African consumers have the right to settle their home loan early at any time without incurring penalty fees. Banks cannot charge early settlement penalties on bonds registered after June 2007.
You can make additional lump-sum payments or increase your monthly payment at any time. Use the Extra Payments tab in the Extended Calculator to see exactly how much you save. Even an extra R500/month on a R1.26M bond at 10.25% over 20 years saves more than R150,000 in interest.
How does the interest rate affect my monthly bond payment?
Every 1% change in interest rate changes your monthly payment by roughly R6–R8 per R100,000 of loan on a 20-year term. For a R1,260,000 bond, a 1% increase in rate adds approximately R800–R1,000 to your monthly payment.
South African bonds are typically variable rate (linked to prime), so when the SARB changes the repo rate, your monthly instalment changes accordingly. Use the rate/term sensitivity matrix in the Professional Simulator (Tier 3) to see the impact of any rate and term combination in one grid.
What does bond insurance cost and is it compulsory?
Banks require you to have home loan (credit life) insurance as a condition of the bond. Under the NCA, the maximum rate for a mortgage is R2 per R1,000 of outstanding balance per month. On a R1,260,000 bond this is R2,520/month initially, declining as the balance falls.
You are entitled to use your own insurer rather than the bank's product. A monthly bank service fee of up to R69 (NCA maximum) may also apply. Both are modelled in the Extended Calculator's Payment Analysis tab.