QuickCalc

Bond Repayment Calculator

Estimate your monthly home loan repayments in South Africa.

Reviewed by The QuickCalc Editorial Team · Last updated · About our methodology

Enter your details

Result

Monthly repayment
R14 630,05
Loan amount
R1 350 000,00
Total interest
R2 161 210,88
Total repaid
R3 511 210,88

Inputs & results at a glance

Updates live as you change the form above.

ItemTypeValue
Property priceInputR1 500 000,00
DepositInputR150 000,00
Interest rateInput11.75%
Loan termInput20 years
Loan amountResultR1 350 000,00
Monthly repaymentResultR14 630,05
Total interestResultR2 161 210,88
Total repaidResultR3 511 210,88

About this calculator

Formula: M = P × r(1+r)ⁿ / ((1+r)ⁿ − 1)

A bond repayment calculator helps you estimate the monthly instalment on a South African home loan before you apply. By entering the property price, your deposit, the interest rate offered by your bank and the loan term, you can immediately see what your monthly bond will cost and how much interest you will pay over the full term.

We use the standard amortisation formula M = P × r(1+r)ⁿ / ((1+r)ⁿ − 1), where P is the loan amount (price minus deposit), r is the monthly interest rate (annual rate ÷ 12) and n is the number of months (years × 12). The result is the equal monthly payment that pays both interest and capital, leaving the loan fully settled at the end of the term.

Most South African banks price home loans relative to the prime lending rate, which is currently around 11.75%. A higher deposit lowers the loan amount, the monthly payment and the total interest. Note that the figure shown here does not include monthly admin fees, life cover, homeowner's insurance, attorney fees or transfer duty — use our Transfer Duty Calculator to estimate those upfront costs.

How to use it

  1. 1Enter the property price. Type the agreed purchase price of the property in Rand.
  2. 2Enter your deposit. Add the cash deposit you intend to put down. The loan amount is the price minus the deposit.
  3. 3Enter the interest rate. Use the rate offered by your bank, or the South African prime rate as a default.
  4. 4Choose the loan term. Most South African bonds run for 20 years. Shorter terms cost less interest but raise the monthly payment.
  5. 5Read the monthly repayment. The result updates instantly and also shows total interest and total repaid.

How it works

A South African home loan (bond) is a fully amortising loan: every rand you pay each month is split between interest on the outstanding balance and a chunk of capital repayment. The calculator starts with the loan amount (property price minus your deposit), converts the annual interest rate to a monthly rate by dividing by 12, and then converts the term in years to a number of months by multiplying by 12. Those three numbers feed into the standard amortisation formula, which returns the single fixed monthly instalment that will pay the loan down to zero at the end of the term.

Because the balance is largest at the start, the interest portion of your monthly instalment is highest in the first years and shrinks over time. That is why paying even a small extra amount into your bond in the early years — for example the first 5 to 7 years of a 20-year term — has an outsized effect on the total interest and can shave several years off the loan. The result panel also shows total interest and total amount repaid so you can see how much the loan really costs beyond the price of the house itself.

Formula

M = P × [ r(1 + r)ⁿ ] / [ (1 + r)ⁿ − 1 ]

P = loan amount (price − deposit); r = monthly interest rate (annual % ÷ 100 ÷ 12); n = total number of monthly payments (years × 12); M = fixed monthly instalment.

Worked examples

R1,500,000 bond over 20 years at 11.75%

Loan amount R1,500,000, no deposit, 11.75% interest, 240 months. Monthly instalment ≈ R16,244. Total interest paid ≈ R2,398,626, total repaid ≈ R3,898,626.

Same bond with a R300,000 deposit

Reducing the loan to R1,200,000 drops the monthly instalment to about R12,995 and cuts total interest by more than R479,000 over the life of the bond.

Frequently asked questions

Is this the same as my actual bond instalment?

It's a close estimate of the capital-and-interest portion. Your bank usually adds a monthly admin fee (around R69 incl. VAT), bond life cover and homeowner's insurance, which push the debit order 5–10% higher.

What interest rate should I use?

Use the actual rate your bank has offered you. If you don't have an offer yet, start with the current South African prime rate (around 11.75%) as a realistic baseline and stress-test at prime + 1% and prime + 2% to see how sensitive your budget is.

How much deposit do I need?

Banks love a 10% deposit and will reward you with a better interest rate, but 100% bonds are common for first-time buyers with clean credit. Remember you also need cash for transfer duty, attorney and bond registration fees on top.

What term should I choose?

20 years is the standard South African home loan term. Shorter terms (15 years) dramatically cut total interest but raise the monthly instalment; longer terms (25–30 years, offered by some banks) lower the instalment but you pay far more in total.

Can I pay off my bond faster?

Yes — bonds are open-ended in South Africa. Paying even R500 extra per month, or depositing an annual bonus, can shave several years off a 20-year term. See our guide on reducing your bond repayments for practical strategies.

What happens if interest rates rise?

Most South African bonds are variable rate, linked to the prime rate. A 1% rate rise on a R1.5 million bond adds roughly R1,050 to the monthly instalment. Recalculate at prime + 2% to check you have a buffer.

Does this include upfront costs like transfer duty?

No. Use our Transfer Duty Calculator to estimate what SARS charges, and ask your conveyancing attorney for a quote covering bond registration, transfer, Deeds Office and postage fees.

Related calculators

Finance

Loan Repayment Calculator

Calculate monthly repayments on personal loans

Property

Transfer Duty Calculator (South Africa)

SARS transfer duty on property purchases

Property

Rental Yield Calculator

Annual gross yield on a rental property

Spotted something off, or want a calculator we don't have?

Send a quick suggestion and it goes straight to the QuickCalc admins.

Suggest a calculator or change