How often should a 13-week cash flow forecast be updated?

Update it at a consistent weekly cutoff. If a material receipt slips or an unexpected payment appears between updates, revise the affected weeks before relying on the forecast for a decision.

Is a 13-week cash flow forecast the same as a budget?

No. This forecast tracks expected bank movements by week. A profit-and-loss budget tracks revenue and expenses, which can be recorded in different periods from the related receipts and payments.

How should overdue invoices be included in cash forecasting?

Place each invoice in a week supported by collection information, such as customer confirmation or resolution of an approval issue. Flag uncertainty rather than assuming every overdue invoice will be paid next week.

Can a weekly forecast miss a cash shortfall?

Yes. A positive weekly closing balance can hide a payment due before receipts arrive that week. When liquidity is tight, check critical receipts and payments by day.

How Does a 13-Week Cash Flow Forecast Work?

Q: How does a 13-week cash flow forecast work?

It starts with available bank cash and projects receipts and payments across 13 weekly periods. Each week, you reconcile actual cash movements, revise future assumptions, and add a new thirteenth week.

A 13-week cash flow forecast tracks expected cash receipts and payments by week, starting with your available bank balance. Each week, you replace the completed week’s estimates with actual cash movements, update the remaining weeks, and add a new thirteenth week. This rolling forecast shows when cash may fall short so you can act on collections, spending, or funding before payments come due.

What goes into a 13-week cash flow forecast?

Build the forecast around bank movements, not accounting revenue or profit. An invoice belongs in the week you expect payment to reach your account, not the week you issue it. A supplier bill belongs in its expected payment week, even if the expense was recorded earlier.

Use one column per week and these core rows:

Opening available cash: money available to make payments at the start of the week.
Cash receipts: customer collections, settlement payouts, and other expected inflows.
Operating payments: payroll, suppliers, rent, taxes, software, and other cash expenses.
Other cash movements: debt payments, equipment purchases, owner distributions, and financing proceeds.
Closing cash: opening cash plus receipts minus payments.

The closing balance of one week becomes the opening balance of the next. Show financing separately so a cash injection does not hide an operating shortfall.

Exclude restricted funds from available cash. If you consolidate several bank accounts, eliminate transfers between them so moving money does not inflate receipts and payments.

How do you build the first version?

Start with reconciled bank balances at a defined cutoff. Then gather open customer invoices, unpaid supplier bills, payroll dates, tax deadlines, debt schedules, and committed purchases.

For collections, assign expected receipt dates using information you can verify: payment terms, customer confirmations, outstanding disputes, and settlement schedules. An overdue invoice is not automatically a receipt next week. Give uncertain receipts a visible status rather than burying uncertainty in a total.

For payments, record the expected bank debit date. Include costs that may not appear in accounts payable yet, such as scheduled payroll or automatic renewals. Do not spread a known payment evenly across weeks just to smooth the forecast.

Give each material line an owner and an assumption. A useful assumption says “customer payment pending invoice approval,” not “management estimate.” That makes the next update a checkable task rather than a fresh guess.

How does the rolling forecast move forward?

A rolling forecast stays useful because its horizon moves with the business. It does not shrink toward a fixed end date.

At the weekly cutoff:

Save the previous forecast so its estimates remain available for comparison.
Enter actual receipts and payments for the completed week.
Reconcile the actual closing balance to available bank cash.
Use that actual balance as the next week’s opening cash.
Revise future receipts and payments using new information.
Add a new week at the end, restoring the full 13-week view.

Do not simply delete the old column and carry forward its projected balance. That carries last week’s error into every future week.

Keep historical actuals in an archive or separate tab. The live view supports decisions; the archive shows whether assumptions are improving and where the same misses keep returning.

What should happen in the weekly cash meeting?

Use the same cutoff and meeting cadence each week. Update the workbook before the meeting, not while everyone watches someone search for invoices.

Assign clear responsibilities:

Finance: reconcile cash, update the model, and explain material differences.
Collections owner: confirm receipt dates and flag disputes or broken payment promises.
Payment owner: identify upcoming obligations and any proposed payment changes.
Founder or decision-maker: approve actions that affect spending, supplier relationships, or financing.

Discuss last week’s misses first, then the lowest projected cash point, then decisions. Review both the closing balance and the obligations that could fall due before incoming cash arrives.

Leave with an action log: what changes, who owns it, and when it must happen. “Follow up on receivables” is not enough. Name the invoice, the person contacting the customer, and the date for obtaining a confirmed payment date.

How do you explain forecast variances?

Compare actual receipts and payments with the version saved before the week began. Keep the sign convention explicit: did the difference leave you with more cash or less cash than forecast?

Separate three causes:

Timing: a receipt or payment moved to another week.
Amount: the cash value changed.
Omission: an item was missing or counted twice.

Each cause requires a different fix. Move a delayed receipt to a supported date; do not leave it in both weeks. Update the underlying assumption when an amount changes. Add a missing obligation and check whether similar obligations are absent elsewhere.

Lower payments are not automatically good news. If bills were merely deferred, the cash requirement has moved forward rather than disappeared.

How does the forecast change founder decisions?

Find the lowest projected cash balance, not just the ending balance in week 13. Compare it with a cash floor defined around your obligations and access to funds, rather than an arbitrary universal buffer.

If cash approaches that floor, identify the driver before choosing the response. Delayed collections call for customer-level action. A discretionary purchase may be rescheduled. A structural gap needs a funding or operating decision, not repeated invoice chasing.

Test proposed changes in a separate scenario. Keep unapproved payment extensions and uncommitted financing out of the base forecast. Once an action is agreed, update its cash date and amount so its effect is visible.

Weekly totals can still hide an intraweek shortfall. When cash is tight, check whether payroll or another critical debit occurs before that week’s expected receipts.

Who should own cash forecasting?

Assign one person to maintain the forecast and one decision-maker to resolve the issues it exposes. The spreadsheet cannot collect an invoice, negotiate terms, or approve a spending pause.

If you need help connecting the weekly model to those decisions, explore John Galt Finance’s fractional CFO services. The goal is a forecast your team can update and act on, not a workbook only its creator understands.

If you’d like a second look at your forecast or weekly cash cadence, book a free 30-minute CFO diagnostic call. Bring your current model, if you have one, and the cash question you need to answer.