A cash flow forecast is a forward look at what will actually land in and leave your bank account over the coming weeks, built from money that's already scheduled: invoices you've sent, bills already on the books, payroll dates you already know. You need one because it turns "I hope payroll clears this month" into "I know exactly which week is tight and what's arriving before it."
What does a cash flow forecast actually look like?
Start with today's bank balance. Then, week by week for the next four weeks, add only the money already scheduled to arrive and subtract only the money already scheduled to leave. Nothing hoped for, nothing projected from a good feeling. A simple version is just five columns:
| Week | Starting balance | Money in | Money out | Ending balance |
|---|---|---|---|---|
| Week 1 | $46,000 | +$3,400 | −$5,600 | $43,800 |
| Week 2 | $43,800 | +$8,200 | −$6,400 | $45,600 |
| Week 3 | $45,600 | +$2,100 | −$5,900 | $41,800 |
| Week 4 | $41,800 | +$9,800 | −$6,400 | $45,200 |
Illustration only, built from scheduled items. Your numbers come from your own invoices and bills.
Do that for four weeks and you have a forecast. That's the whole machine.
Why it changes how you run the business
Almost every business has a rhythm: a stretch of the month where the first payroll clears before customer payments land, and the balance dips. Most owners feel that dip as a knot in the stomach. A forecast turns it into a known event with a date on it. Once you can see the tight week coming, you can move a payment, chase an invoice, or delay a purchase before the squeeze instead of during it. The forecast rarely changes what happens. It changes whether it happens to you or in front of you.
What's real and what's assumed
The discipline that makes a forecast trustworthy is keeping two things separate and visible: what's already true, and what you're assuming. A sent invoice is scheduled, but whether it lands on the exact day you expect is still an assumption, because clients pay late. "That client usually pays around the 20th" is a reasonable assumption, but name it as one. A forecast built on named assumptions can be wrong in ways you can learn from. A forecast built on optimism can only surprise you.
Cash flow forecast vs. budget
They're not the same tool. A budget is a plan for a whole year: what you expect to earn and spend across twelve months. A cash flow forecast is a short-range, week-by-week look at the actual money moving through your bank right now. A budget tells you whether the year is on track. A forecast tells you whether you can cover next Thursday. You want both, and they answer different questions.
When to look at it
Once you've built the template, it's about five minutes a week, same day each week. It's not a report you file, it's a glance at the road ahead. Owners who do this stop being surprised by their own bank account, and that alone changes how growing feels.