Finance

How to Build a Cash Flow Forecast for a Growing Business

A cash flow forecast tells you when money comes in, when it goes out, and how much runway you have. Here is a practical way to build one.

In short: Use the actual bank position as the opening balance. A forecast built on an inaccurate starting point is immediately unreliable.

Time receipts realistically

Forecast customer receipts based on payment behaviour, not invoice date. If customers normally pay in 45 days, model 45 days.

Map committed outflows

Payroll, tax, supplier payments, rent, debt service and recurring software should be timed according to when cash actually leaves.

Add scenarios

Model base, upside and downside cases. Include the effect of delayed collections, hiring, price changes and large projects.

Update it

A cash forecast is a management tool, not a one-time spreadsheet. Update assumptions as reality changes and compare forecast to actual.

Start with the cash movements, not the accounting labels

A useful cash-flow forecast shows when cash is expected to enter the bank, when it must leave, and the resulting balance. Revenue and profit matter, but timing matters just as much. A profitable company can still face cash pressure if customers pay slowly while payroll, VAT, suppliers or investment are due earlier.

Build three views

ScenarioPurposeTypical question
Base caseYour current best estimateIf the plan broadly works, how much cash will we have?
Growth caseModels upside and the cost of supporting itIf sales accelerate, what working capital or hiring is required?
Downside caseTests resilienceIf revenue is late or lower, when does cash become constrained?

Model the assumptions you can manage

Useful inputs include invoice timing, collection days, recurring revenue, gross margin, hiring dates, supplier terms, tax/VAT timing, financing, capital spend and one-off projects. Make the assumptions visible so management can challenge them rather than treating the forecast as a black box.

Update it when decisions change

A forecast is not an annual document. Update it when actual performance materially changes the assumptions, when a major hire or investment is approved, when collection behaviour changes or when the business takes on a new commitment. The purpose is to support decisions before cash becomes a surprise.

What to do next

If this problem looks familiar, use Find My Rework to identify where the issue sits across finance, cost, process, people, technology and execution — or book a conversation if you already know what you need.