Start with your bank balance today. List the cash you expect to receive each week (from customers, by how they pay), then every payment going out: wages, Payday Super, rent, suppliers, loan repayments, BAS (GST and PAYG withholding) and income tax instalments. The closing balance each week becomes next week's opening balance. Use a 13-week forecast to manage the next quarter and a 12-month forecast to plan. Update it weekly against what actually happened.
Key takeaways
- A 13-week forecast is for running the business. A 12-month forecast is for planning it.
- Forecast cash, not profit: when money actually lands and leaves, including GST.
- Build in the big lumps: BAS, PAYG instalments, insurance, and super within 7 business days of each payday from 1 July 2026.
- Recurring revenue is the most forecastable cash you have. Model it from members, churn and payment method.
- Every week, compare forecast to actual and fix the assumptions that were wrong.
For years I ran a business with great sales and terrible cash flow. Some months we were flat out. Other months I was working out how to pay everyone. I wrote The Subscription Playbook because of what fixed it: enough revenue arriving automatically, every month, to cover the rent, the wages and the software before the month even started.
But even before you get there, there's one habit that changes everything. Know your cash position for the next 13 weeks. This guide shows how to build that forecast, step by step, with the Australian lumps (BAS, PAYG, super) that catch owners out.
Download the free 13-week cash flow template (Excel)
Cash flow forecast vs budget vs profit and loss
| What it shows | Timing | |
|---|---|---|
| Profit and loss | Whether you made money | When income is earned and expenses incurred |
| Budget | What you plan to earn and spend | Usually monthly, for the year |
| Cash flow forecast | Whether you'll have money in the bank | When cash actually arrives and leaves |
A profitable business can still run out of cash. Customers pay late. Stock is bought before it's sold. GST collected in one quarter is paid weeks later. The forecast is what shows you the gap before you fall into it.
Step 1: Pick your horizon
- 13 weeks (one quarter), week by week. This is your operating forecast. It's detailed enough to catch a tight week, and short enough to be accurate.
- 12 months, month by month. This is your planning forecast: hiring, a new fit-out, a quiet season, a loan.
Most small businesses should keep both, and update the 13-week one every Monday.
Step 2: Start with today's real bank balance
Use the actual balance across your operating accounts, not what Xero says your profit is. If you keep a separate tax account (you should), you can show it separately, or treat it as already spent.
Step 3: Forecast cash in
List every source of cash, by week:
- Recurring revenue. Memberships, plans, retainers. Model it from the number of active customers × price, less expected churn, by billing date.
- Annual renewals. Which annual plans renew in which week, and how many usually do.
- One-off sales. Base them on recent weeks and your pipeline, not your hopes.
- Debtors. Invoices you've issued, by when they'll actually be paid. Use your real collection pattern. If most clients pay in 45 days, don't assume 14.
- Other. GST refunds, grants, asset sales, owner contributions, loan drawdowns.
Include GST in cash receipts. The customer pays you the GST-inclusive amount. You'll pay the GST out later, in the BAS line.
Step 4: Forecast cash out
Then every payment, in the week it actually leaves your account:
- Wages (net pay) on each payday.
- Super. From 1 July 2026, under Payday Super, super for employees must be received by their fund within 7 business days after each payday. That replaces the old quarterly timing, so it's now a weekly or fortnightly line, not a quarterly lump.
- PAYG withholding from wages, paid with your BAS (monthly or quarterly).
- GST on your BAS, net of GST credits.
- PAYG income tax instalments, if the ATO has put you in the system.
- Rent, utilities, software, insurance on their due dates.
- Suppliers and stock, based on your actual payment terms.
- Loan and lease repayments, including interest.
- Owner drawings or wages. Put yourself in the forecast. You're a cost too.
- Annual and irregular items: insurance premiums, registrations, accountant's fees, equipment.
Step 5: Work out the closing balance
For each week:
Opening balance + cash in − cash out = closing balance
The closing balance becomes next week's opening balance. Add a row for your minimum safe balance, the cushion you never want to go below. Highlight any week that drops under it.
A worked example: a physio clinic
A clinic starts the quarter with A$42,000 in the bank. It has 300 patients on a A$59 monthly wellness plan paid by direct debit on the 1st, plus casual consults of about A$18,000 a week.
| Week | Cash in | Cash out | Of which BAS | Closing | Note |
|---|---|---|---|---|---|
| 1 | A$35,700 | A$31,000 | A$46,700 | Plan debits A$17,700 land | |
| 2 | A$18,000 | A$29,500 | A$35,200 | Payroll and super | |
| 3 | A$18,000 | A$24,000 | A$29,200 | ||
| 4 | A$18,000 | A$44,500 | A$16,000 | A$2,700 | BAS + payroll same week |
| 5 | A$35,700 | A$27,000 | A$11,400 | Plan debits land |
Week 4 is the problem. The business is profitable, but BAS and payroll fall in the same week and the balance nearly hits zero. Spotting that eight weeks early means the owner can move the BAS payment date (by lodging and paying on the due date, not early), chase debtors, delay a purchase, or move some patients to annual plans. Spotting it in week 4 means a phone call to the bank.
Notice what the A$17,700 of wellness plan revenue does. It arrives automatically on the 1st, whatever the weather. That's the line that makes a forecast reliable, and it's the line most worth growing.
Want help building your forecast?
A BPAG Accountants adviser can walk through your cash flow with you in a free 30-minute profit review.
Forecasting recurring revenue properly
If you have memberships, plans or retainers, forecast them from the drivers, not a lump:
- Active customers at the start of the period, by plan and billing date.
- New customers you expect each week.
- Churn: the percentage who cancel each month. Use your actual history. The churn calculator helps.
- Failed payments: the share of debits that fail and how many you recover.
- Payment timing: card payments usually settle in a few days; BECS direct debits take longer; PayTo is near real time.
- Annual plans: model renewals by month, with your renewal rate. Annual plans are great for cash, but they create lumps, and the GST on them is due on your next BAS. See subscriptions and cash flow.
The weekly routine
Every Monday, 20 minutes:
- Update the opening balance from the bank.
- Replace last week's forecast with actuals.
- Note where you were wrong and why.
- Roll the forecast forward a week.
- Act on any week that falls under your safe minimum.
After a few weeks, your forecasts get much more accurate, because you're learning your business's real patterns.
Common mistakes
- Forecasting profit instead of cash. Depreciation isn't cash. Loan repayments are.
- Forgetting GST. It's in your receipts and it leaves in a lump.
- Optimistic debtors. Use when customers actually pay, not your terms.
- Leaving out the owner. If you don't pay yourself in the forecast, it isn't real.
- Not updating it. A forecast from three months ago is a historical document.
Tools
A spreadsheet is enough for most small businesses. Our free 13-week template has the rows above, a safe-minimum check and formulas you can extend. Xero, MYOB and add-ons like Float or Fathom can automate parts of it once you outgrow a spreadsheet. Business Victoria also publishes a free cash flow forecasting template.
Free Subscription Profit Review
Australian business owners can book a free 30-minute review with a BPAG Accountants adviser. An honest conversation about:
- whether a subscription model could work for your business
- how recurring revenue could cover your fixed costs each month
- how it could lift what your business is worth
No cost, no obligation. General information only until we understand your situation.
Frequently asked questions
How do I do a cash flow forecast for a small business?
Start with today's bank balance. Forecast cash coming in each week from customers, based on how and when they actually pay. Forecast every payment going out, including wages, super, BAS, tax instalments, rent and loans. Opening balance plus cash in minus cash out gives the closing balance, which carries to the next week.
What is a 13-week cash flow forecast?
It's a week-by-week forecast covering the next quarter. It's detailed enough to show tight weeks, such as when BAS and payroll fall together, and short enough to be reasonably accurate. Update it weekly.
Should GST be included in a cash flow forecast?
Yes. Your receipts include GST and your supplier payments include GST credits. The net GST is then paid in a lump with your BAS. Leaving GST out makes your cash look better than it is until the BAS is due.
How does Payday Super affect cash flow?
From 1 July 2026, employers must pay super so it's received by the employee's fund within 7 business days after each payday, instead of quarterly. Super becomes a regular line in your forecast with every payroll, rather than a quarterly lump.
What's the difference between a cash flow forecast and a budget?
A budget sets out what you plan to earn and spend, usually on a profit basis. A cash flow forecast shows when money will actually move in and out of your bank account, so you can see whether you'll have enough cash at each point.
General information only, current as at 29 October 2026. It isn't legal, tax or financial advice and doesn't consider your circumstances. Speak to a qualified adviser before acting.
Talk it through with a BPAG adviser
Free for Australian business owners: a 30-minute Subscription Profit Review on whether a subscription suits your business.
Robert Coorey, MBA
Robert is the author of The Subscription Playbook and Feed a Starving Crowd and a Director at BPAG Accountants in Sydney. More about Robert.
Sources and further reading
- ATO, Paying super for your employees (Payday Super)
- ATO, Managing, paying GST and your cash flow
- Business Victoria, Cash flow forecasting template
- NAB, Cash flow forecast template
- The Subscription Playbook, Robert Coorey (2022), Chapter 1
Sources checked 29 October 2026. Spotted something out of date? Tell us.