The 13-week cash flow forecast every founder should run
Founders rarely fail from being unprofitable. They run out of cash while profitable. The 13-week forecast catches the gap four weeks before it hits.
8 min read
Why 13 weeks?
Thirteen weeks is one quarter, long enough to see trouble coming, short enough to forecast with real accuracy. It's the horizon that catches the payroll you can't make before you can't make it.
What goes in it
A 13-week forecast is cash in minus cash out, week by week:
Starting cash for the week
Inflows: customer payments you realistically expect to collect (not invoices you've sent)
Outflows: payroll, rent, taxes, vendor payments, loan payments
Ending cash, which becomes next week's starting cash
The discipline that makes it work
Forecast collections, not invoices. A net-60 client who "owes" you today is cash nine weeks from now.
Update it weekly. Replace last week's estimate with what actually happened. A forecast you touch once is a guess.
Watch the low point. The scariest number isn't week 13, it's the lowest week in between. That's your real runway.
What it prevents
Payroll every two weeks, clients paying in 60 days, and no one modeling the gap. Run the 13-week and the gap stops being a surprise, you see it four weeks out, and you have four weeks to do something about it.
