Cash Flow Forecasting: A Simple Guide for Business Owners

Most business owners know roughly how much money is in the bank today. Far fewer know what their bank balance will look like in three months. Cash flow forecasting fills that gap. It’s a simple way to predict the cash coming in and going out of your business, so you can spot shortfalls early and plan ahead.

A good forecast turns cash from a monthly worry into something you can manage. This guide explains what a cash flow forecast is, how to build one step by step, and how to use it to make better decisions.

What is cash flow forecasting?

Cash flow forecasting means estimating the timing and amount of cash that will move in and out of your business over a set period. Typically, businesses look 13 weeks or 12 months ahead.

It’s different from a profit and loss statement. Your P&L shows whether you made a profit. Your forecast shows whether you’ll have enough cash in the bank to pay bills on time. A business can be profitable and still run short of cash, which we explain in why your business can be profitable but have no cash.

Why a cash flow forecast matters

Cash problems rarely appear overnight. Usually, the warning signs are there weeks or months earlier. A forecast therefore helps you see them in time to act.

In particular, a cash flow forecast helps you:

• See shortfalls before they happen, not after.
• Plan for big payments like BAS, income tax, super and insurance.
• Decide whether you can afford to hire, buy equipment or expand.
• Have better conversations with your bank or lender.
• Know how much you can safely pay yourself.

Most importantly, it gives you time. A shortfall you spot three months out is a planning problem. A shortfall you discover on payday is a crisis.

How to build a cash flow forecast step by step

You don’t need complex software to start. A spreadsheet or the forecasting tool in your accounting software is enough. The business.gov.au cash flow guide also has a free template you can adapt. Then follow these steps.

1. Choose your time frame

A rolling 13-week forecast is ideal for managing day-to-day cash. A 12-month forecast is better for bigger decisions and tax planning. In fact, many owners use both.

2. Start with your opening bank balance

First, use the actual cash in your business accounts today. However, don’t include money you’re owed but haven’t received yet.

3. Estimate cash coming in

List the cash you expect to receive each week or month. Base it on when customers actually pay, not when you send the invoice. Include:

• Customer receipts from existing invoices.
• Expected new sales, based on realistic patterns.
• Other inflows, such as GST refunds, loans or asset sales.

4. Estimate cash going out

Next, list everything you expect to pay and when. Remember to cover:

• Wages, PAYG withholding and superannuation.
• Supplier bills, rent and subscriptions.
• Loan repayments and lease payments.
• GST, PAYG instalments and income tax.
• Owner drawings or salary.

5. Calculate the closing balance

For each period, take the opening balance, add cash in and subtract cash out. The closing balance then becomes the next period’s opening balance. Any negative figure is a warning sign that needs a plan.

6. Add a minimum cash buffer

Decide on the lowest balance you’re comfortable holding, such as one or two months of fixed costs. Then mark any period where the forecast drops below that line. This gives you an early trigger to act, well before the account actually runs dry.

Cash flow forecasting tips for better accuracy

A forecast is only useful if you trust it. These habits will keep yours realistic.

• Use real payment patterns. If customers usually pay in 45 days, forecast 45 days, even if your terms say 14.
• Be conservative with sales. It’s safer to underestimate income and overestimate costs.
• Don’t forget tax. Set aside GST and PAYG as you collect it, rather than treating it as spare cash.
• Update it weekly. Replace estimates with actual figures and roll the forecast forward.
• Compare actual with forecast. After all, big gaps show where your assumptions need work.

Your forecast also works best alongside a budget. Our guide to small business budgeting in Australia shows how the two fit together.

Using your cash flow forecast to make decisions

Once your forecast is in place, it becomes a decision-making tool rather than just a report. For example, you can test “what if” scenarios:

• What happens if a major customer pays 30 days late?
• Can we afford a new staff member from March?
• Should we buy equipment outright or finance it?
• How much do we need to put aside for the next tax bill?

Planning for tax is one of the biggest wins. Instead of a surprise bill, you’ll see it coming months ahead. Read our tips on how to avoid a big tax bill to get started.

If your forecast shows a gap, act early. You might chase debtors faster, change payment terms, delay a purchase or talk to your lender. Our guides on how to improve business cash flow and managing business debt cover these options in more detail.

Common cash flow forecasting mistakes

Even experienced owners fall into these traps:

• Forecasting profit instead of cash.
• Forgetting quarterly and annual payments, such as BAS, insurance and registrations.
• Assuming every customer pays on time.
• Building the forecast once and never updating it.
• Leaving owner drawings out of the numbers.
• Ignoring seasonal swings, such as a quiet January or a busy end of financial year.

Fortunately, each of these is easy to fix once you know to look for it. A quick monthly review with your accountant can catch most of them.

Who should prepare your cash flow forecast?

Many owners build the first version themselves, and that’s a great way to understand the business. Over time, though, it helps to share the load. Your bookkeeper can keep actual figures up to date each week. Meanwhile, your accountant or advisor can check the assumptions, add tax payments and help you plan around them.

The key is that someone owns it. A forecast that nobody updates quickly becomes stale and loses its value. If you’d rather not do the numbers yourself, our article on bookkeeping options for busy owners may help.

Next step: get a clear view of your cash

Cash flow forecasting is one of the simplest ways to take control of your business. Yet it’s often the first thing to slip when you’re busy.

Our Business X-Ray looks at your numbers, your cash flow and your tax position together. We’ll show you where cash is getting stuck and how to plan ahead with confidence. Book your Business X-Ray and stop waiting for your accountant to call once a year.

Cash flow forecasting FAQs

How far ahead should a cash flow forecast go?

A rolling 13-week forecast suits day-to-day management. For bigger decisions, such as hiring or tax planning, extend it to 12 months.

What’s the difference between a budget and a cash flow forecast?

A budget sets targets for income and expenses over the year. A cash flow forecast predicts when cash will actually land in or leave your bank account.

How often should I update my forecast?

Ideally weekly, or at least monthly. Regular updates keep it accurate and help you spot problems early.