Build a 13-week cash flow forecast and see funding needs coming

Most urgent funding requests have a warning sign somewhere in the business’s recent past: a slow customer, a big BAS, an extra pay run, a stock order that arrived before the sales. The problem is that nobody was looking in the right place at the right time.

A 13-week cash flow forecast is the right place. It’s a simple spreadsheet that shows, week by week, what’s coming in, what’s going out and what the bank balance will be. It turns “I think we’ll be tight in November” into “we’ll be $42,000 short in the week of 23 November, and back in the black by 7 December” (illustrative). That’s the difference between an emergency and a plan.

Why cash, not profit

Your profit and loss statement tells you whether the business makes money. It doesn’t tell you when the money arrives. Business.gov.au describes managing cash flow as making sure you always have enough to pay your expenses, debts and yourself — which is a question of timing, not profitability.

A profitable builder can be short of cash because progress claims take seven weeks to be paid. A profitable retailer can be short because Christmas stock is paid for in October. A profitable consultancy can be short because a government client’s first payment takes three months. The forecast shows the timing; the P&L doesn’t.

Why 13 weeks

Thirteen weeks is a quarter. It’s long enough to include:

• A full BAS cycle — for most quarterly lodgers, 28 October, 28 February, 28 April or 28 July.
• Six or more weekly pay runs, or several fortnightly ones.
• Super under Payday Super, which since 1 July 2026 must reach funds within 7 business days of each payday.
• Most customer payment terms.
• Rent, insurance and loan repayments.

And it’s short enough that your estimates are reasonably reliable. Beyond three months, forecasts drift into guesswork.

Step 1: set up the columns

Create a spreadsheet with one column per week for 13 weeks, starting this Monday. Down the side, create three blocks: cash in, cash out, and the running balance.

	Week 1	Week 2	Week 3	…	Week 13
Opening balance
Cash in (total)
Cash out (total)
Closing balance

The closing balance of each week becomes the opening balance of the next.

Step 2: list cash coming in

Be specific and conservative:

• Customer receipts — use actual payment behaviour, not invoice terms. If a customer on 30-day terms usually pays in 45 days, forecast 45.
• Card and cash sales — use the same weeks last year as a guide, adjusted for growth.
• Other receipts — GST refunds, insurance payments, asset sales, owner contributions.

Put each item in the week you realistically expect the money to land in your bank, not the week it’s due.

Step 3: list cash going out

This list is usually longer than people expect:

• Wages in each pay week.
• Super — under Payday Super, within 7 business days of each payday. Put it in the week it will actually leave.
• PAYG withholding and GST — in the week your BAS is paid.
• Suppliers — by their actual due dates.
• Rent and outgoings.
• Loan and equipment finance repayments.
• Insurance, registrations, subscriptions — annual items are easy to forget.
• Owner drawings.

Step 4: find the low point

Once every line is in, look at the closing balance row. The lowest number is your key figure.

• If it never goes below your comfortable minimum, you don’t need funding this quarter.
• If it dips below, the size of the dip is your funding need, and the number of weeks until it recovers suggests the term.
• Add a buffer. Late payers are the rule, not the exception.

Step 5: choose the right response

Not every gap needs a loan. Try these first:

• Bring receipts forward — invoice faster, chase earlier, ask for deposits on large jobs.
• Push payments back — negotiate supplier terms, where it’s fair to do so.
• Defer spending — delay a non-urgent purchase by a few weeks.

What’s left after those steps is the genuine gap. Then match it to a funding structure:

Gap pattern	Suggested structure
One-off, clear end	Short unsecured loan or working capital loan
Recurring each quarter or month	Line of credit
Large relative to turnover	Property-secured loan
Tied to one contract	Loan sized to the contract, repaid from its payments

If your forecast shows a gap in the next few weeks, talk to a specialist now — early conversations have the most options.

Step 6: update every week

A forecast is only useful if it’s current. Every Monday:

1. Replace last week’s forecast figures with actuals.
2. Add a new week 13 at the end.
3. Adjust any receipts that have moved.
4. Check the new low point.

Ten minutes a week. Over time, comparing forecast with actual shows you which customers pay late, which costs creep and how accurate your estimates are.

A worked example (illustrative)

A landscaping company with eight staff pays wages weekly, super within 7 business days, and has a BAS due at the end of October. Its main commercial client pays monthly, around 40 days after invoice.

The forecast shows a comfortable balance through week 3, then a dip as the BAS payment and two pay runs land in week 5 while the commercial client’s payment doesn’t arrive until week 7. The lowest closing balance, in week 6, is about $38,000 below the owner’s minimum comfort level. By week 8 the balance recovers.

The owner has three options: ask the client for faster payment (possible, not guaranteed), defer a trailer purchase from week 4 to week 9 (saves $12,000 in the gap), and arrange a line of credit for the remaining $26,000 plus a buffer. The facility is set up in week 1, drawn in week 5 and repaid in week 8. Because it was arranged early, the owner compared options calmly rather than borrowing under pressure.

Scenarios: best case, expected, worst case

Once the basic forecast works, copy it twice and change a few assumptions:

• Expected: your realistic view, as built above.
• Slow payers: move your two largest customer receipts back by two to three weeks.
• Quiet trade: reduce card or cash sales by a meaningful but plausible amount.

The gap in the worst of those scenarios is the funding you’d want available, not necessarily drawn. It’s often the right size for a line of credit limit: enough to cover a bad few weeks, used only when needed.

Scenario planning also helps with conversations. A lender or specialist who sees that you’ve already tested a slow-payer scenario knows you understand your business, and that tends to speed things up.

Sharing your forecast with a lender

You don’t need a polished document. A clean spreadsheet with the 13 weeks, a line or two explaining the main assumptions, and a note on what the funding would be used for is plenty. Include the scenario that drives your request, and highlight the week the balance recovers — that’s the exit.

Common forecasting mistakes

• Forecasting invoices instead of receipts. Customers pay when they pay.
• Forgetting annual costs. Insurance, registrations and licence renewals.
• Treating super as quarterly. Under Payday Super, it follows every pay run.
• Ignoring the GST in your takings. It’s collected for the ATO and leaves at BAS time.
• Building it once and never updating it.

Where to go next

Our 2026–27 business cash calendar lists the dates to put in your forecast. The Fast Business Loan Navigator turns a funding gap into a likely pathway and speed. And if payroll is the pressure point, see funding payroll and super.

See the gap, then close it calmly

A forecast gives you time; time gives you choices. Enquiring doesn’t involve a credit check, your details aren’t blasted around a panel of lenders, and a real specialist can look at your forecast with you and suggest the structure that fits your gap — not just the first product available. Please share accurate figures on the form, especially turnover and the size of the gap. See if you qualify.