A smart guideline used by South African banks and lenders is the 30% rule:
No more than 30% of your gross monthly income should go toward your home loan repayments.
But don’t guess — use these two calculators below to get accurate numbers and feel confident about your next move.
Which one should come first?
Start with the 30% calculator to set a safe monthly repayment limit. Then use the affordability calculator to see if that number realistically aligns with what banks might offer — based on your full financial picture.
Together, they help you stay grounded while shopping for your dream home.
Step 1: Use the 30% Income Calculator
This gives you a quick rule-of-thumb limit based on your income, so you know what monthly bond repayment is considered financially safe.
Great for:
Early-stage budgeting
First-time buyers who want a fast estimate
Understanding what 30% of your income actually looks like
Simply enter your gross monthly income to see what 30% of it amounts to — a useful guideline for the maximum bond repayment you should aim not to exceed.
How much of your income is safe for a bond?
Enter your gross monthly income:
Step 2: Use the Affordability Calculator
Once you’ve got a rough number from Step 1, the Affordability Calculator takes it further.
It factors in:
Your income
Your expenses
The interest rate
Loan term
This gives you a more accurate loan amount you could be approved for by a bank.
Step 3: Compare the two amounts
Now that you’ve used both calculators, here’s how to bring the results together and understand what they mean for your budget (the figures below are used for example purposes only).
From Step 1: 30% of Income
Let’s say your gross monthly income is R20,000.
30% of that is R6,000
That’s your recommended limit — your monthly bond repayment should ideally not exceed R6,000 to stay financially comfortable.
From Step 2: Affordability Calculator result
Here’s an example input:
Gross income: R20,000
Net income: R17,680
Monthly expenses: R5,000
Interest rate: 10.75%
Loan term: 20 years
Based on this, the affordability calculator estimates you could qualify for a home loan of around R591,000.
The monthly repayment would be approximately R6,000.
How to compare your results
| Calculator | What it shows |
|---|---|
| 30% Income Calculator | R6,000 — your recommended monthly limit |
| Affordability Tool | R591,000 loan ≈ R6,000/month repayment |
In this case, the numbers match up — the estimated loan repayment fits within your safe spending range, meaning you're looking at a bond you can realistically afford without stretching your budget.
What if the loan repayment is higher?
If the affordability calculator shows a repayment over R6,000, that’s a red flag.
You might:
Be approved for too much
Be stretching beyond a safe budget
Risk falling into debt stress later
Stick to the 30% rule to stay in control and avoid future financial strain.
Final thoughts: play it smart, not just hopeful
Buying a home is one of the biggest financial commitments you'll ever make. That’s why it’s not just about what the bank might give you — it’s about what fits comfortably in your budget month after month.
Here’s our best advice:
Always plan with realistic numbers, not wishful thinking.
Factor in future expenses like levies, maintenance, and interest rate hikes.
Use both tools — the 30% calculator to set your ceiling, and the affordability calculator to see how close reality gets.
Smart buyers take control early. Start with clarity, stay informed, and move with confidence.
Know your rights under SA credit law
Lenders in South Africa are legally required to check your ability to afford a home loan before offering you credit. These affordability checks are mandated by the National Credit Act (2005) and enforced by the National Credit Regulator (NCR). To learn more about your rights and how credit providers conduct these assessments, explore the NCR’s Education and Communications section.
