When a turnaround professional walks into a struggling company, the first artifact they build is not a budget, a strategy deck, or a cost-cutting plan. It is a 13-week cash flow forecast. Before anyone decides anything, they want to know one thing: when, exactly, does the money run out?
You should not wait until someone is asking that question about your business to have the answer.
Here is the uncomfortable math on how thin most cushions are. The median US small business holds 27 cash buffer days — enough cash to survive about four weeks if inflows stopped tomorrow. A quarter of small businesses hold 13 days or fewer. Restaurants sit at a median of 16 days (JPMorgan Chase Institute, 470 million transactions across 597,000 businesses). And in the Federal Reserve's most recent Small Business Credit Survey, roughly half of employer firms named uneven cash flow as a recurring financial challenge.
A 13-week forecast will not add a dollar to your bank account. What it does is convert surprises into decisions — it shows you the bad week while it is still six weeks away and fixable, instead of Thursday when payroll is due.
Why 13 weeks, specifically
One quarter. That is the horizon where forecasting is still honest.
Shorter — a two-or-four-week view — only confirms problems you can already feel. Longer — a 12-month projection — is mostly fiction past the first quarter, built on revenue you have not booked from customers you have not met. Thirteen weeks is the working compromise the restructuring profession settled on decades ago: long enough to see trouble while you can still act on it, short enough that every number in it is real.
It is a weekly view, not monthly, and that matters more than it looks. Cash problems are weekly problems. A month that nets out fine on paper can contain a week 2 where rent, payroll, and a quarterly tax payment land together while your biggest customer's check does not. Monthly forecasts hide exactly the thing you need to see.
Before you build: three inputs you already have
You do not need software, a bookkeeper on standby, or clean historicals. You need three things, and you can gather them in half an hour:
Your bank balance. Today's actual number, from the account you pay bills from. Not what QuickBooks thinks — what the bank says.
Your receivables, with honest dates. Every open invoice, and the week you genuinely expect the cash — which is not the due date. If that customer always pays 20 days late, forecast them 20 days late. (You are in large company: a recent QuickBooks survey of nearly 2,500 small businesses found 56% were owed money on outstanding invoices — $17,500 per business on average, and nearly half of those had invoices already 30+ days past due.)
Your bills calendar. Payroll dates, rent, loan payments, insurance, tax deadlines, the credit card, your regular suppliers. Most of this repeats — which is what makes the forecast mostly reusable once built.
The build, step by step
This walkthrough mirrors our free 13-Week Cash Flow Tracker — you can build the same thing in a blank spreadsheet, but the template has the formulas, the flags, and an example already wired.
Step 1 — Set the frame. Thirteen columns, one per week, starting Monday of this week. Top row: beginning cash — this week's column is your actual bank balance; every later week begins with the prior week's ending balance.
Step 2 — Forecast receipts. Cash coming in, by the week it actually arrives: customer collections (from your dated receivables list), then everything else — deposits, refunds, that loan draw. Rule of the whole exercise: book receipts in the week the cash lands, not the week you earn it. An invoice is not money.
Step 3 — Forecast disbursements. Cash going out, by week: payroll (with the payroll-tax lines that ride along), rent, suppliers, loan payments, insurance, taxes, subscriptions, owner draws. Walk your last two months of bank statements to catch the ones you forgot — there are always two or three.
Step 4 — Let the math run. Each week: beginning cash + receipts − disbursements = ending cash, which becomes next week's beginning cash. In the template this is prewired; in a blank sheet it is one formula copied across.
Step 5 — Draw the line. Decide your minimum comfortable cash — the level below which you cannot make payroll plus a normal week's bills. Put it in as a line. The template compares every week's ending cash against it and raises a LOW flag on any week that dips under. That flag, six weeks out, is the entire point of the document.
Reading it: three signals, three moves
The dip week. One week flags LOW, then recovers. A timing problem, not a business problem. Move: shift the collision — request one deposit earlier, schedule one payment later, and watch that week weekly until it passes.
The stair-step down. Ending cash declines week over week across the sheet. That is not timing — the business is consuming cash. Move: this is a margin-and-volume conversation, and the forecast just gave you a number for how many weeks you have to have it.
The cliff. Cash holds, then one week craters — usually a tax deadline, an insurance renewal, an annual anything. Move: you now know the date; start setting aside for it weekly, beginning this week.
The Friday ritual
An afternoon builds the forecast. Twenty minutes a week keeps it alive — and the weekly ritual is worth more than the original build.
Every Friday: replace this week's forecast with actuals, note where you were wrong, adjust the coming weeks with what you learned, and add week 14 so the horizon stays 13 weeks long. The first month, your forecasts will miss. By week six, you will know your business's cash rhythm better than you ever have — which customers really pay when, which weeks are structurally tight, what your true minimum balance is.
When the forecast says trouble
If the flags are real and the ladder of ordinary moves — accelerating receivables, negotiating payment timing, trimming the discretionary — does not clear them, do not spend six months alone with a spreadsheet that keeps saying the same thing. Cash problems compound quietly. Whether it is your accountant, your banker, or us, the businesses that come through cash crunches are the ones that started the conversation while the forecast still showed six weeks of runway.
Download the free 13-Week Cash Flow Tracker — the template from this walkthrough with the formulas, LOW flags, and a worked example included. Free with an EZ account. When you are ready for the full version with the receipts detail, scenario view, and variance tracking, code CASHFLOW20 takes 20% off.