Bond repayment calculator
Work out your monthly repayment, compare loan terms and see how your balance falls over time. Adjust the interest rate to match your bank offer.
Home Loan Parameters
Deposit Ratio: 10.0% • Principal Loan: R1 980 000
R20 102 / month
Annuity Formula Applied:
M = P × [r(1 + r)^n] / [(1 + r)^n - 1] where r = 0.8958% monthly and n = 240 months.
Yearly Bond Amortisation Table (20-Year Schedule)
| Year | Opening Balance | Annual Instalments | Annual Interest | Principal Repaid | Closing Balance | Home Equity |
|---|---|---|---|---|---|---|
| Year 1 | R1 980 000 | R241 218 | R211 410 | R29 809 | R1 950 191 | 11.4% |
| Year 2 | R1 950 191 | R241 218 | R208 043 | R33 176 | R1 917 015 | 12.9% |
| Year 3 | R1 917 015 | R241 218 | R204 295 | R36 923 | R1 880 092 | 14.5% |
| Year 4 | R1 880 092 | R241 218 | R200 124 | R41 094 | R1 838 998 | 16.4% |
| Year 5 | R1 838 998 | R241 218 | R195 482 | R45 736 | R1 793 262 | 18.5% |
Statutory & Credit Disclaimer: Calculations are indicative estimates provided for South African property budgeting only and do not constitute formal financial or legal advice under FAIS. Final home loan terms are subject to lender credit approval and affordability verification under the National Credit Act (Act 34 of 2005). Conveyancing, bond registration, Deeds Office, and SARS Transfer Duty figures are subject to statutory tariff adjustments.
South African Bond Repayment Formula & Amortisation Mechanics
Major South African home loan lenders (Standard Bank, FNB, Absa, Nedbank, SA Home Loans, and Investec) structure residential mortgages as reducing-balance annuities. During the first 7 to 10 years of a 20-year bond at 10.75% Prime, the majority of every monthly instalment services interest rather than capital reduction.
Standard Annuity Repayment Equation:
M = P × [r(1 + r)^n] / [(1 + r)^n − 1]
- • M = Base Monthly Bond Instalment (excluding R69 NCA service fee)
- • P = Principal Loan Amount (Purchase Price minus Deposit in ZAR)
- • r = Monthly Interest Rate (Annual Nominal Rate ÷ 12)
- • n = Total Number of Monthly Instalments (Loan Term in Years × 12)
Next Steps Before Signing an Offer to Purchase (OTP)
In addition to your monthly bond instalment, ensure you budget for upfront SARS Transfer Duty, conveyancing attorney tariffs, municipal rates, and pre-purchase compliance inspections:
Frequently Asked Questions: South African Bond Repayments & SARB Prime
How is a monthly home loan repayment calculated in South Africa?
South African retail banks calculate monthly mortgage repayments using the standard monthly-compounded annuity formula: M = P × [r(1 + r)^n] / [(1 + r)^n − 1], where P is the principal loan amount in Rand, r is the monthly interest rate (annual rate divided by 12), and n is the total number of monthly instalments (e.g. 240 months for a 20-year bond). In addition, banks charge a statutory National Credit Act (NCA) monthly service administration fee of R69.00 (incl. 15% VAT).
What is the current South African Prime Lending Rate?
The South African Prime Lending Rate is benchmarked at 350 basis points (3.50%) above the South African Reserve Bank (SARB) Repo Rate. With a default Prime Rate of 10.75%, borrowers with strong credit scores and substantial deposits may negotiate interest concessions of Prime minus 0.50% to Prime minus 1.25%.
Should I choose a 20-year or 30-year home loan term in South Africa?
A 20-year (240-month) home loan is the standard benchmark in South Africa. Extending your bond to 30 years (360 months) reduces your monthly instalment by roughly 8% to 10%, but dramatically increases total cumulative interest paid over the life of the loan by more than 60%.
How do extra monthly payments or an access bond reduce total interest?
Because South African banks calculate mortgage interest on the daily outstanding capital balance and capitalise it monthly, paying even R1 000 extra per month into your bond directly reduces the principal balance, shaving years off a 20-year amortisation schedule and saving hundreds of thousands of Rands in cumulative interest.