13-week cash flow forecast: template and how to build one

Free 13-week cash flow forecast template (Excel)

13-WEEK CASH FLOW FORECAST - [Company] - weeks starting [date]
One column per week, Week 1 to Week 13, then a Total column.

OPENING CASH
  Week 1: today's bank balance. Every later week: last week's closing cash.

RECEIPTS
  Customer payments on open invoices    by the week you expect the money
  Customer payments on new sales        sales not invoiced yet
  Other receipts                        tax refunds, asset sales, interest
  Financing in                          loan drawdowns, new equity
  TOTAL RECEIPTS

PAYMENTS
  Payroll and payroll taxes             on the pay dates
  Supplier bills                        by due date or planned payment date
  Rent and other fixed costs            on their due dates
  Sales tax / VAT and other taxes       on the filing dates
  Loan repayments and interest          from the loan schedule
  Owner draws                           what you plan to take out
  Equipment and other capital spending  when you will pay, not when you order
  TOTAL PAYMENTS

NET CASH FLOW        total receipts - total payments
CLOSING CASH         opening cash + net cash flow

MINIMUM CASH BUFFER  the lowest balance you are willing to hold
HEADROOM             closing cash - minimum cash buffer

Where does each line of the forecast come from?

• Customer payments on open invoices come from the aged receivables. Place each invoice in the week you expect the money, using how that customer actually pays rather than the due date; the DSO calculator shows the average delay across all customers.
• Customer payments on new sales are sales you expect to invoice during the 13 weeks, placed at the invoice date plus the usual delay. Keep them on their own line so you can see how much of the forecast is not billed yet.
• Payroll comes from the payroll calendar, including the employer's taxes on their own payment dates.
• Supplier bills come from the aged payables, placed on the date you plan to pay them, plus regular costs whose bills have not arrived yet.
• Taxes, loans and equipment come from their own calendars: filing dates, the loan schedule, purchases already approved. These are the lumpy payments a monthly view smooths over.

Worked example: Northbridge Analytics, 13 weeks from October 5, 2026

• $1,454,444 to $1,267,863: the balance at the start of week 1 and at the end of week 13, a change of −$186,581.
• Low point $1,267,863, in week 13. This is the number to hold against your minimum cash buffer.
• The same receipts and payments every week. The sample's outlook carries a steady weekly run rate. In your own forecast, place each invoice, bill, payroll and tax payment in its own week: that is where the dips between month ends appear.

What does the weekly update involve?

1. Roll it forward. Drop the week that has ended and add a new week 13, so the forecast always looks a full quarter ahead.
2. Put in the actuals. Replace last week's forecast with what really came in and went out, and note the difference.
3. Refresh the inputs. Update receipts from the latest aged receivables and payments from the latest bills and payroll.
4. Find the low point. Compare the lowest closing balance with your minimum cash buffer.
5. Decide. If headroom gets thin: chase the largest overdue invoices, agree new dates with suppliers, delay discretionary spending, or arrange funding early.

What mistakes make a 13-week forecast wrong?

• Forecasting profit instead of cash. Revenue is not receipts; costs are not payments. Use the dates money moves.
• Assuming customers pay on the due date. Use each customer's real habits; a forecast built on due dates is optimistic by default.
• Forgetting the irregular payments. Quarterly taxes, annual insurance, bonuses and loan balloons are exactly what the 13 weeks are for.
• Building it once. A forecast that is not rolled forward and checked against actuals stops being trusted.

Or have it written for you

• Your ledger. QuickBooks Online and Xero; NetSuite, Sage Intacct, Zoho Books and Business Central in beta.
• Every month on the 1st. The report is refreshed on the 1st of every month for the month just ended, as a draft that waits for your approval.
• History from day one. The first connection reads the trailing 24 months, so the first report already compares each month with the same month last year.
• Cash, 13 weeks out. A weekly cash forecast beside the open invoices and bills falling due.
• A second reviewer. A second, independent AI reviewer reads every monthly narrative, and an AI explanation that cites a source outside your books is discarded, not published.