The 13-week cash flow forecast: see every pinch point a quarter ahead

Most cash crises don’t arrive out of nowhere. The BAS was always going to be due on the 28th. The big supplier invoice was always on 30-day terms. The slow month after Christmas happens every year. What makes them feel sudden is not seeing them coming.

A 13-week cash flow forecast fixes that. It’s the single most useful financial habit a small business can build, it takes about an hour to set up, and it changes the way you make decisions — including whether, when and how much to borrow.

What is a 13-week cash flow forecast?

It’s a simple grid. Weeks run across the top — this week plus the next twelve. Down the side are the ways cash comes in and goes out. At the bottom is the bank balance, rolled forward week by week.

The number that matters most is the lowest point: the week when the balance is at its thinnest. That’s your early warning. If the lowest point is comfortably positive, you can plan with confidence. If it’s close to zero or negative, you’ve found a problem weeks before it becomes an emergency.

Thirteen weeks is a quarter. That’s long enough to capture a full BAS cycle, several pay runs and most supplier terms, but short enough to forecast week by week with reasonable accuracy. business.gov.au offers a free template for a current or forecast cash flow statement if you’d rather not start from a blank page.

How do you build one in an hour?

Step 1: Start with today’s real bank balance. Use the actual figure from online banking, across all business accounts you use for day-to-day trading.

Step 2: List cash in, by week. Think about when money actually arrives, not when you invoice.

• Customer receipts, based on how quickly each customer really pays.
• Card and platform settlements.
• Any other expected receipts — tax refunds, insurance payments, asset sales.

Step 3: List cash out, by week.

Category	What to include	Timing tip
Wages	Net pay for each pay run	Match your actual pay cycle
Super	Super guarantee for each pay run	From 1 July 2026, Payday Super moves super onto the pay cycle
Tax	BAS, PAYG instalments, income tax	Quarterly BAS: 28 Oct, 28 Feb, 28 Apr, 28 Jul
Rent and fixed costs	Rent, insurance, subscriptions, utilities	Use the actual debit dates
Suppliers	Stock, materials, services	Based on the terms you actually pay on
Loan repayments	Existing loans, leases, cards	Daily and weekly debits add up
Owner drawings	What you take out personally	Easy to forget, important to include

Step 4: Roll the balance forward. Opening balance plus cash in minus cash out equals closing balance, which becomes next week’s opening balance.

Step 5: Find the lowest week. Highlight it. That’s the number to manage.

Already spotting a pinch point? Start a 60-second enquiry and a specialist can talk through options — no credit check when you first enquire.

How do you make the forecast accurate?

A forecast is only useful if you trust it. A few habits make a big difference:

• Be conservative with cash in. If a customer usually pays ten days late, forecast ten days late.
• Be complete with cash out. Scroll through the last three months of bank transactions for anything you’ve forgotten — annual insurance, software renewals, registrations.
• Separate GST. Remember that part of what customers pay you belongs to the ATO at BAS time.
• Update weekly. Replace last week’s forecast with actuals, add a new week at the end, and note where you were wrong.
• Keep it simple. Twenty well-chosen rows beat two hundred you never update.

If your books are up to date in cloud software, much of this can be pulled from your bank feed and aged receivables. Our page on using accounting software data covers what to tidy up first.

What do you do when you find a pinch point?

Seeing a low week coming gives you choices you don’t have when it’s already arrived:

1. Speed up cash in. Chase specific overdue invoices, invoice faster, or offer an early-payment incentive to one large customer. Our guide to e-invoicing covers one practical way to shorten the wait.
2. Move cash out. Ask a supplier to shift a payment by a week, delay discretionary purchases, or time a stock order after a big receipt.
3. Talk to the ATO early if a BAS payment is the problem, and lodge on time regardless.
4. Arrange finance before you need it. A facility arranged three weeks ahead is calmer, often cheaper and more likely to be the right structure than one arranged in a panic.

The forecast also shows the right shape of finance. A single dip that recovers when a big invoice is paid suits a short-term loan. A dip that repeats every month or every season suits a line of credit. See fast working capital loans for how to match product to gap.

How does a forecast help when you do borrow?

It turns a vague request into a clear one. Instead of “we need about $60k for cash flow”, you can say: “we’ll dip to minus $45k in week seven when the BAS and a supplier payment coincide, and recover in week nine when the government contract pays”. That tells a lender how much you need, for how long, and how it will be repaid.

It also lets you test a loan’s repayment schedule before you sign. Lay the repayments over the forecast and check the lowest week again. Our guide to daily and weekly repayments walks through that test.

An illustrative example

Illustrative only. A small engineering services firm builds its first 13-week forecast in early October. The owner expects the quarter to be fine — sales are strong. The forecast tells a different story.

In week four, the quarterly BAS for July–September falls due in the same week as a large materials invoice. Two big customers pay on 45-day terms, so their receipts don’t arrive until week seven. The balance is forecast to dip well below zero in weeks four to six, then recover strongly.

Seeing this in week one, the owner does three things. He calls one customer, who agrees to pay part of an invoice early. He asks the materials supplier to split its invoice across two weeks. And he arranges a short facility sized to the remaining gap, with repayment timed for week seven. The quarter passes without a single late payment — and without the stress.

How do you keep the habit going?

Put fifteen minutes in the diary at the same time every week. Update actuals, roll the forecast forward, check the lowest point, and write one line about anything that changed. After a month it becomes routine. After a quarter you’ll wonder how you ran the business without it.

Which mistakes make forecasts misleading?

• Forecasting invoices instead of receipts. An invoice raised isn’t cash in the bank.
• Forgetting annual and quarterly costs such as insurance, registrations and BAS.
• Leaving out owner drawings, which makes the business look healthier than it is.
• Being optimistic about new sales that aren’t yet confirmed.
• Never checking forecast against actual. Without that loop, errors repeat.

Avoid these and your forecast will quickly become something you trust — and act on.

Want a specialist to look at your forecast?

A forecast shows you the gap; the right finance closes it without creating a new one. Send the 60-second enquiry and a real person will look at your numbers and tell you honestly whether finance is the right move and what shape it should take. There’s no credit check when you first enquire, and your details go to one specialist rather than being fired off to a list of lenders. Share accurate figures — your forecast is only as good as its inputs, and so is our advice.

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