PRACTICAL GUIDE · OCTOBER 7, 2026

How to build a 13-week cash flow forecast

A cash forecast answers a practical question: will money arrive before the bills fall due? Start with your current cash, place expected collections and payments in the weeks you expect them, and update the plan as reality changes.

Gather the dates before the totals

Choose a consistent start day for each of the next thirteen weeks. Gather available cash, unpaid customer invoices, likely collection dates, supplier bills, payroll, rent and recurring payments. Use expected collection dates rather than invoice dates. Keep confirmed amounts separate from estimates in your notes.

Include relevant transfers, owner withdrawals and financing payments in the weeks they affect cash. Avoid counting the same payment in both a bank export and a bill list. For tax amounts or financing decisions, use your actual records and advice from your accountant.

Calculate each week

Ending cash = opening cash + expected receipts − expected payments. The next week begins with the previous week's ending cash. A forecast is an estimate, so record the assumptions behind uncertain dates.

The business ends week one with only $500. If the $4,000 collection moves from week two to week three, week two instead ends at −$1,300. The eventual receipt may be unchanged, but the timing gap needs attention before payments are due. These figures are illustrative, not a prediction for your business.

Make the forecast a weekly routine

1. Replace the completed week's estimates with actual cash movements.
2. Reconfirm outstanding collection dates and upcoming payments.
3. Review the lowest projected balance and any assumptions that could change it.
4. Assign an owner and date to each follow-up, such as confirming a customer's payment date.
5. Add a new week so the plan keeps looking thirteen weeks ahead.

Start free, then choose a longer planning view

The free weekly tracker is a simple starting point. The $9 13-week cash forecast is a separate editable Excel workbook with instructions, a fictional example and a blank working copy. Its license is for internal use within one business. It does not connect to your bank or accounting system.