Cash-Flow Fundamentals
The 13-Week Cash-Flow Forecast Every Owner Should Run
Short answer
A 13-week cash-flow forecast lists every expected cash inflow and outflow by week for the next quarter. It is the gold-standard tool used by turnaround consultants because it forces you to see exactly when (not if) a shortfall will hit.
Most small businesses run on a monthly P&L view — too coarse to catch a cash gap. A weekly forecast over 13 weeks (a full quarter) gives you enough runway to act, and updates in 10 minutes a week once set up.
What to include
- Starting cash balance each week
- Expected customer collections by week (use your invoice list and typical pay timing)
- Recurring outflows: payroll, rent, insurance, subscriptions, loan payments
- Variable outflows: materials, subcontractors, fuel
- Tax set-aside transfer (treat it as an outflow)
- Owner draws
- Ending cash balance each week
How to use it
Run it every Monday. Compare last week's forecast vs actuals — variances tell you where your assumptions need tuning.
When ending balance dips below your safety threshold (typically 4 weeks of fixed costs), trigger a collections push and slow non-critical outflows.
Frequently asked questions
What tool do I use?
A spreadsheet is fine. Google Sheets, one row per line item, columns for each of 13 weeks.
Cash flow you can see.
Glo Invoice surfaces AR aging, upcoming cash, and overdue invoices on one dashboard — free for 14 days.
Sources & further reading
Primary sources we consulted when writing and reviewing this guide.