Running the Numbers on a Rental Property in South Africa: A Step-by-Step Beginner’s Guide

Running the numbers on a rental property in South Africa is the single most important skill you can develop as a property investor. It is what separates investors who build wealth from those who buy properties that quietly drain their income for years. And the good news is that once you understand the process, it takes about 15 minutes to assess any deal with confidence.

In this blog I am going to walk you through the exact steps using real South African numbers so you can start applying this immediately.

Step 1 — Find Out What the Property Can Rent For

Before you can run any numbers, you need a realistic rental estimate. Do not rely on what the seller or agent tells you. Go to Property24 and search for similar properties for rent in the same area, same size, same type, same condition. Look at what is currently listed and what has recently been let. This gives you a market-based rental figure rather than an optimistic one.

For a R900,000 apartment in a Johannesburg suburb, a realistic market rental might be R7,000 to R8,000 per month. Use the conservative end of the range for your calculations.

Step 2 — Calculate Your Monthly Bond Repayment

Your bond repayment is typically your largest monthly expense. Use an online bond calculator, ooba’s free bond calculator is straightforward and South Africa-specific. Input the purchase price, your deposit amount, and the current interest rate.

At the current prime lending rate of approximately 11.25 percent, a R900,000 bond over 20 years would cost approximately R9,200 per month. If you have a 10 percent deposit of R90,000, your bond would be R810,000 and the repayment approximately R8,300 per month.

Step 3 — List All Your Monthly Expenses

This is the step most beginners skip and it is why they end up surprised. Your full expense list should include:

• Bond repayment — R8,300 in our example
• Municipal rates — approximately R400 to R600 per month for a standard apartment
• Levies — if applicable, can range from R500 to R2,000+ depending on the complex
• Building insurance — approximately R200 to R400 per month
• Property management — 8 to 10 percent of rental, so R560 to R700 on R7,000 rental
• Maintenance provision — 5 percent of rental, approximately R350 per month
• Vacancy provision — divide one month’s rental by 12, approximately R583 per month

Total estimated monthly expenses in our example: approximately R11,000 to R12,500 depending on the specific property.

Step 4 — Calculate Your Monthly Cash Flow

Subtract total monthly expenses from monthly rental income.

Cash Flow Calculation Example R7,000 (rental) MINUS R11,500 (total expenses) = MINUS R4,500 per month This deal is cash flow negative at full asking price with no deposit contribution beyond 10%

In this example, the deal does not stack up at R900,000 with a 10 percent deposit. This does not necessarily mean it is a bad property, it means you either need to negotiate the price down, increase the deposit to reduce the bond, or find a property with stronger rental income relative to its price.

This is exactly why running the numbers before you fall in love with a property is so important. The analysis tells you the truth before your emotions commit you to a decision.

Watch on YouTube: Running The Numbers On A Rental Property Using A Quick Formula

Step 5 — Calculate the Rental Yield

Even if cash flow is tight, rental yield tells you whether the property is fundamentally well-priced relative to its rental income.

Gross Yield Calculation Example R7,000 x 12 = R84,000 per year divided by R900,000 x 100 = 9.3% gross yield A 9.3% gross yield is above the 8% benchmark, the property is reasonably priced for its rental income

A gross yield of 9.3 percent tells you the property is not overpriced relative to its rental. The cash flow problem in this example comes from the financing cost, a larger deposit or a lower purchase price would change the picture significantly.

What Good Numbers Look Like

As a general guide for South African buy-to-let investments:

• Gross rental yield of 8 percent or above — property is well priced for its rental
• Net rental yield of 5 percent or above — solid after expenses
• Cash flow neutral or positive — sustainable without topping up from your salary
• Vacancy rate below 5 percent in the area — demand from tenants is strong

Not every deal will tick all four boxes perfectly. But understanding where a deal falls short helps you negotiate better, structure your finance differently, or walk away with confidence.

The Bottom Line

Running the numbers on a rental property in South Africa takes 15 minutes once you have a system. That 15 minutes is the most valuable time you will spend on any property decision. If you want to learn this process in detail including how to use a deal calculator and analyse different property types such as buy to let, student accommodation and flips, then course below is the next step.

Ready to learn? How To Run Numbers and Analyse A Property Deal — R897