Start with what you actually know: your current bank balance and any cash you expect to come in over the next few weeks or months. Then list every expense you know is coming. That’s the foundation of any cash flow forecast, and you build from there.

Pull up your bank statements and accounting records from the last three to six months. Look at when money actually hits your account, not when you send invoices. If your customers typically pay 30 days after you invoice them, your forecast needs to reflect that delay. The same goes for expenses. Some bills hit on the first of the month, others are irregular. Your historical records show you these patterns.

Build your forecast in a simple spreadsheet or use QuickBooks reporting features. Create columns for each week or month going forward depending on how tight your cash situation is. If cash is tight, use weekly columns for at least the next 13 weeks. If you’re more stable, monthly columns for 6 to 12 months work fine.

For each period, list your expected cash inflows. This includes customer payments based on your current receivables and pipeline, recurring revenue, and any other income. Be realistic here. Not every proposal turns into a signed contract, and not every invoice gets paid on time. Use your actual collection history to estimate timing rather than best-case assumptions.

Then list every cash outflow. Rent, payroll, insurance, loan payments, materials, subcontractor payments, taxes, and owner draws. Don’t forget quarterly estimated tax payments or annual expenses like insurance renewals. These lumpy costs are often what creates the cash crunches that surprise business owners.

Subtract outflows from inflows for each period and carry the running balance forward. This rolling balance is the whole point. It shows you exactly when you might run short and how much cushion you have. If you see a negative balance three months out, you have time to act now instead of scrambling later.

A common mistake is confusing profit with cash flow. You can have a profitable month and still run out of cash if your customers haven’t paid yet or you had to buy materials upfront for a big project. The forecast captures this timing reality that a profit and loss statement doesn’t show.

The forecast itself is only useful if you update it. Review it every week or two and replace your projections with actual numbers as they come in. Adjust future periods based on what’s changed. A QuickBooks ProAdvisor in Chandler can help you set up the initial framework in a way that’s easy to maintain, but the discipline of reviewing and updating regularly is what gives you real visibility into your business.

If building and maintaining a forecast feels like more than you want to take on yourself, budgeting and cash flow forecasting as an outsourced service takes that off your plate entirely. You get updated projections and someone interpreting the numbers for you so you can focus on running your business and making decisions with confidence.