If there is one financial tool that I would give every South African SME owner above all others, it is not a better income statement. It is not a more detailed budget. It is a cash flow forecast.
A cash flow forecast is simply a forward-looking view of what money is coming into your business and what money is going out — week by week — over the next rolling 13 weeks. It does not tell you what happened. It tells you what might or is about to happen. This is a big difference. Looking backwards and looking forwards, is the difference between reacting to financial problems and preventing them. Having said that, they are both important.
Here why every SME needs one and how to build a simple version that you can start using immediately. They can be notoriously complicated but no one wants that.
Why 13 weeks?
The 13-week is chosen for good reason. Thirteen weeks is one quarter. It is long enough to see seasonal patterns, upcoming large payments and the impact of current decisions on future cash. It is short enough to be accurate. No crystal balls needed. Twelve-month forecasts for SMEs tend to be exercises in optimism rather than useful planning tools. Remember, NEVER build anything on hopes and dreams. Thirteen weeks is the sweet spot.
Maintaining a rolling 13-week cash flow forecast, may sound daunting. I simply means that at the end of each week, you drop the week that has passed and add a new week at the end, so you always have a 13-week forward view – the rolling 13 weeks. This becomes one of the most powerful early warning systems available to a South African business owner.
A 13-week cash flow forecast does not eliminate uncertainty — it illuminates it. You can see problems coming three months away rather than discovering them three days before payroll.
What a cash flow forecast actually looks like
Here is a simplified example of what a 13-week cash flow forecast looks like for a service business:
| Week | Money in | Money out | Net movement | Closing balance |
| Week 1 | R 42 000 | R 38 500 | R 3 500 | R 87 500 |
| Week 2 | R 0 | R 28 000 | (R 28 000) | R 59 500 |
| Week 3 | R 68 000 | R 22 000 | R 46 000 | R 105 500 |
| Week 4 | R 15 000 | R 55 000 | (R 40 000) | R 65 500 |
| … | … | … | … | … |
| Week 13 | R 55 000 | R 31 000 | R 24 000 | R 142 000 |
The opening balance in week 1 is R84 000. Each week shows projected cash in, cash out and the net movement. The closing balance rolls forward as the opening balance of the following week. Very quickly, you will notice that week 2 is a negative cash week — more going out than coming in — and that the closing balance drops to R59 500. That is not necessarily a problem, but it is information. You know about it in advance. You can act.
What goes into the cash in column
Cash in is not the same as revenue. Cash means any money coming into your bank account. If it does not happen in the bank account, it doesn’t go in the cash flow forecast. It is the cash you expect to actually receive in that specific week. It is NOT from invoices raised. This distinction is critical and it is where many first-time forecasters go wrong.
Your cash in should include: expected payments from current debtors based on their payment history and your payment terms, any deposits or advance payments due on upcoming projects, any other expected cash receipts such as asset sales, loan drawdowns or tax refunds.
Do not include an invoice as cash in the week you raise it. Include it in the week you realistically expect to receive payment. If a client consistently pays on day 45 despite 30-day terms, forecast their payment on day 45.
What goes into the cash out column
Cash out is every rand you expect to pay out in that week — to suppliers, staff, landlords, SARS, the bank and everyone else. Again, I cannot stress this enough, if it does not happen in the bank account, it doesn’t go in the cash flow forecast. It includes payroll on the specific payroll date that you pay the amount, supplier payments based on your creditor terms, rent on its due date, VAT201 payments on their due dates, loan repayments on their scheduled dates and any capital expenditure planned for the period. If a payment is missed, you do not include it. Why? Because it did not come out of your bank account.
The discipline here is precision. Details matter. Do not spread costs evenly across weeks. Put them in the week they actually fall due. Payment might be paid early. A company might pay their VAT on the 23rd of the month, not the last day. A R45 000 VAT payment on a specific date creates a very different cash picture in that week than if it were spread across four weeks.
The power of a cash flow forecast is in the detail. Spreading costs evenly destroys the insight. Put each payment in the exact week it falls due — that is where the early warning comes from.
How to build your first 13-week forecast — a six-step process
| 1 | Start with your opening balance | Your current bank balance as of today. This is week one’s opening balance. |
| 2 | List all expected cash inflows | Go through your debtors list. For each outstanding invoice, estimate the week payment will arrive based on the client’s payment pattern. Add any other expected receipts. |
| 3 | List all expected cash outflows | Pull your supplier invoices due, your payroll date, your rent, your loan repayments, your VAT due dates and any other committed expenditure. Put each in the exact week it falls due or when expected to be paid. |
| 4 | Calculate the net movement each week | Cash in minus cash out. Positive means cash is building. Negative means you are drawing down your balance. |
| 5 | Roll the closing balance forward | Each week’s closing balance becomes the next week’s opening balance. This gives you a continuous 13-week view of your cash position. |
| 6 | Review and update weekly | Drop the week that has passed, add a new week at the end, and update figures as actuals become known. The forecast improves in accuracy as you maintain it consistently. |
Using Xero to support your forecast
Xero does not have a built-in 13-week cash flow forecasting tool in the standard package, but it provides all the underlying data you need to build and maintain one. Your debtors ageing report tells you exactly what is outstanding and how long it has been due. Your creditors report tells you what you owe and when. Your bank feed gives you an accurate opening balance at any point.
Some Xero add-ons — including Spotlight Reporting and Float — integrate directly with Xero and provide purpose-built cash flow forecasting. For businesses that want a more automated approach, these tools are worth exploring. These may add value but may also cost money to have. If it saves you time, then way up the cost to benefit ratio.
For most SMEs starting out with forecasting, a well-maintained spreadsheet connected to your Xero data is a perfectly adequate starting point. The discipline of building and reviewing the forecast matters more than the tool you use to maintain it.
Want help building your first 13-week cash flow forecast? Book a free discovery call with BC Accounting Services at bcas.co.za — we will build it with you and show you how to maintain it.
About the author
Bruce is the founder of BC Accounting Services (BCAS), a Xero Partner and Certified Adviser based in South Africa. He works with SME owners and growing businesses to build financial clarity, strategic direction and measurable performance — through the PCP Method: Purpose, Clarity, Performance.
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