Bond vs Invest Calculator South Africa
Should you pay extra off your bond or invest the spare cash? Compare net wealth outcomes over 10, 20 or 30 years — with TFSA, JSE, RA, and access bond analysis
| Year | Bond: Remaining Balance | Bond: Net Wealth | Invest: Portfolio | Invest: Net Wealth |
|---|---|---|---|---|
| Year 1 | R 1 155 596 | R 344 404 | R 25 131 | R 344 375 |
| Year 3 | R 1 051 960 | R 448 040 | R 83 564 | R 447 722 |
| Year 5 | R 924 855 | R 575 145 | R 154 874 | R 574 117 |
| Year 7 | R 768 967 | R 731 033 | R 241 901 | R 728 703 |
| Year 9 | R 577 776 | R 922 224 | R 348 107 | R 917 769 |
| Year 11 | R 343 289 | R 1 156 711 | R 477 721 | R 1 149 005 |
| Year 13 | R 55 701 | R 1 444 299 | R 635 900 | R 1 431 820 |
| Year 15 | R 0 | R 1 500 000 | R 828 941 | R 1 777 721 |
| Year 17 | R 0 | R 1 500 000 | R 1 064 526 | R 2 200 782 |
| Year 19 | R 0 | R 1 500 000 | R 1 352 031 | R 2 718 220 |
| Year 20 | R 0 | R 1 500 000 | R 1 518 738 | R 3 018 738 |
Bond net wealth = property value minus remaining bond balance (with extra payments). Invest net wealth = normal bond equity plus investment portfolio. Property value held constant — actual property appreciation will benefit both strategies equally.
Pay Off Bond vs Invest: The South African Dilemma Strategy • Tax efficiency • Access bonds
How to Use This Calculator
Enter your bond balance, interest rate, remaining term, and the extra monthly amount you have available. The Bond vs Invest tab shows the net wealth outcome under each strategy over your chosen horizon. The Decision Matrix tab weighs six key factors — spread, risk, liquidity, tax vehicle, age, and access bond — to give a personalised recommendation.
The Core Trade-Off
Paying extra into your bond saves you interest at your bond rate (currently prime = 10.25%). This is a guaranteed, risk-free return. Investing the same amount earns a variable return — JSE equity has averaged around 12% per annum over 20-year periods, but with significant volatility. The decision hinges on after-tax investment return vs bond rate.
At 10.25% prime, paying extra into the bond saves 10.25% guaranteed. A JSE index tracker earns ~12% but is taxed (dividend withholding, CGT on sale). Inside a TFSA, the same 12% is tax-free — which typically tips the balance in favour of investing, provided you have not exhausted your R36,000 annual TFSA contribution limit.
Worked Example — Ayanda's Decision
Ayanda has a R1,200,000 bond at 10.25% with 20 years remaining. She has R2,000/month spare cash to deploy.
Option A — Pay extra into bond: Term reduces by approximately 4 years 2 months. Interest saving: ~R220,000. Net wealth after 20 years (bond paid off, property owned outright): value of property.
Option B — Invest R2,000/month in TFSA at 10%: Portfolio grows to approximately R1,520,000 over 20 years. Net wealth = normal bond equity + R1,520,000 portfolio.
In Ayanda's case, the TFSA route produces higher net wealth because 10% tax-free beats 10.25% guaranteed. If she had an access bond, she could do both: pay extra and redraw if needed.
Frequently Asked Questions
Should I pay extra into my bond or invest in South Africa?
It depends on the rate spread. At 10.25% prime, paying extra into your bond saves 10.25% guaranteed and risk-free. If your investment can return more than 10.25% after tax — possible with a TFSA or long-term JSE investment — investing can produce higher net wealth. The access bond is often the best middle ground: pay extra in and keep the option to redraw.
How does the TFSA R36,000 limit affect the bond vs invest decision?
The Tax-Free Savings Account (Section 12T) allows up to R36,000 per year (R500,000 lifetime cap). Growth inside the TFSA is completely free of income tax, dividends withholding tax, and capital gains tax. This makes the effective return significantly higher than outside a TFSA. Once your TFSA is maxed, the calculus changes — taxable investments may no longer beat the bond rate after tax, especially at higher marginal rates.
What is an access bond and how does it help?
An access bond (also called a flexi bond) allows you to redraw the extra capital you have paid in, up to your original bond limit. This means you can pay extra into the bond — earning the guaranteed interest saving — while keeping the option to access those funds if needed. Standard Bank, Absa, and Nedbank all offer access bond facilities. It is arguably the best combined strategy for most South African homeowners with spare cash.
Does marital regime affect the bond vs invest decision?
Yes. Under community of property (COP), all assets and liabilities are jointly owned. Paying off the bond reduces joint debt and is often the simpler, lower-risk option. Under an antenuptial contract (ANC), each spouse's investments can be held separately, which may allow better tax structuring (two separate TFSA limits, separate RA contributions). For COP couples, joint financial decisions are needed before moving large sums into individual investment accounts.
How does a Retirement Annuity compare for the bond vs invest decision?
An RA contribution is tax-deductible up to 27.5% of taxable income (capped at R350,000/yr). This means a R2,000/month RA contribution effectively costs much less after tax — for someone at the 36% marginal rate, the net cost is only R1,280/month. This dramatically improves the effective return and typically makes RA contributions competitive with or superior to paying extra on the bond, especially for earners in the 36–45% tax brackets. The major downside: RA funds are locked until age 55.