How to Build a 13-Week Cash Forecast You Can Update

Build a 13-week cash forecast by placing expected receipts and payments into the weeks when money should reach or leave the bank. Start with supported available cash, carry each week's closing balance into the next opening balance, and review the lowest point. Update actual results every week and add another week so the horizon continues to cover 13 weeks.

For an established business, the useful output is a dated decision: whether payroll, a supplier commitment, or an equipment payment fits the expected cash path. This guide provides a direct receipts-and-payments worksheet and a review routine. Our cash-flow statement guide addresses the different task of interpreting historical financial statements.

Choose one cutoff and define opening cash

Use 13 consecutive weekly periods with explicit start and end dates. Decide which bank accounts belong in the forecast and reconcile their opening amounts to bank and accounting records. Identify outstanding payments, deposits in transit, and restricted amounts so the same item is not counted twice or assumed available without support.

Keep undrawn borrowing separate from cash already held. If a draw is part of a scenario, identify the lender conditions, approval, expected availability date, and repayment consequences. An unapproved request is not an assured receipt. Use a separate scenario for funding still under discussion.

The SEC's financial-statement guide explains that income and cash flow answer different questions and that depreciation is a noncash adjustment. This forecast is an original management worksheet, not a required financial-statement format. It follows expected bank movements instead of starting from projected profit.

Build receipts from invoices and collection evidence

List major customer receipts individually with customer, invoice, amount, expected bank week, evidence, and collection owner. Separate issued invoices from forecast sales that have not yet been billed. Consider billing timing, payment terms, known disputes, customer commitments, and settlement delays before assigning a receipt week.

For smaller recurring receipts, use a documented grouping supported by recent collection patterns. Preserve the assumptions behind the total. Do not count both a customer invoice and the processor settlement that pays it. Transfers between included company accounts also need elimination so they do not inflate total business receipts.

Place payments by their actual cash timing

Start with payroll calendars, supplier commitments, rent, insurance, debt schedules, and planned asset purchases. Obtain tax payment amounts and timing from the responsible advisor. Include owner transfers when authorized and relevant. A monthly expense divided by four can conceal a payment concentrated in one week.

Separate committed payments from proposed spending, but retain both in the relevant scenario. Exclude depreciation from cash payments. If a card charge will be settled through a later card payment, choose a consistent cash treatment that avoids counting the purchase and the card settlement as two bank outflows.

Original example: all 13 weeks in view

Hypothetical illustration: an established business begins with $50,000 available cash. Every figure in the table is in thousands of dollars. Receipts and payments are invented weekly totals; payments include all obligations assumed for this simplified scenario. There are no transfers, restricted funds, new loans, or unlisted transactions. The owner selects $20,000 as an internal review threshold, not a universal reserve recommendation.

Week	Opening	Receipts	Payments	Closing
1	50	30	35	45
2	45	25	40	30
3	30	35	50	15
4	15	45	30	30
5	30	30	35	25
6	25	40	35	30
7	30	35	40	25
8	25	45	35	35
9	35	30	40	25
10	25	40	35	30
11	30	35	40	25
12	25	45	35	35
13	35	35	40	30

Week 3 checks as $30,000 + $35,000 − $50,000 = $15,000. Across the horizon, receipts total $470,000 and payments total $490,000. Ending cash is $50,000 + $470,000 − $490,000 = $30,000. The lowest weekly closing balance is $15,000 in week 3, which falls $5,000 below the chosen review threshold even though week 13 ends above it.

Suppose $15,000 of week 3 receipts moves to week 4. Week 3 would close at zero; week 4 would return to the original $30,000 because the delayed receipt arrives then. The ending horizon total hides the earlier squeeze. Weekly closing balances can also conceal an intraweek shortfall, so examine daily timing around the tightest week.

Review variance, then roll forward

At the next weekly review, replace week 1 forecasts with actual receipts and payments and reconcile the closing balance. Explain differences by amount and timing. A receipt delayed into week 2 needs its forecast date updated; a lost sale should not simply be shifted forward forever.

Keep the previous version before moving the horizon. Remove the completed week, add a new week 13, and update material assumptions throughout. Assign collections to the credit owner, supplier dates to operations, payroll to the payroll owner, and payment decisions to an authorized manager. Accounting maintains the reconciled starting point and the trail of changes.

Turn the lowest balance into a decision

For the example, investigate the week 3 gap before approving discretionary spending. Test a documented collection action, a mutually agreed supplier schedule, or a smaller proposed purchase. Show the revised weekly balances and identify any conditions. Do not treat moving a payment in a spreadsheet as permission to miss an obligation.

Bring the current invoice list, payment commitments, and assumptions to TaxBowl's CFO advisory service. The review can connect the forecast to a specific decision and establish who will update it. For the operating reasons cash becomes tied up, see our profit and cash guide.

Keep the supporting invoices, payment records and asset schedules behind these assumptions. The IRS recordkeeping guide describes records supporting business entries; the forecast itself remains a management worksheet.

The accompanying Clara CFO Group video demonstrates general receipts-and-payments forecasting, including inventory, owner transfers, minimum cash and timing scenarios. Its monthly illustration can be adapted to weekly periods; use the dates and assumptions in your own records.