The template, free
Five tabs: assumptions, AR register, AP register, the 13-week grid, and a Monday routine. Real formulas, no email wall.
What it is, and why thirteen weeks
A 13-week cash flow forecast is a week-by-week projection of every dollar entering and leaving your bank accounts for the next quarter. Not accrual revenue, not P&L expenses — cash, on the weeks it actually moves.
Thirteen weeks is not arbitrary. It's one quarter: long enough to see a payroll crunch, a tax payment, and an annual premium coming; short enough that you can still be honest line by line. Push the horizon to six months and every number past week sixteen is fiction. Pull it to four weeks and you find problems after the point where you could fix them cheaply. Thirteen weeks is where honesty and foresight overlap — which is why turnaround specialists, lenders, and CFOs all converged on the same number.
Ask any CFO who works with $1M–$25M businesses and you'll hear the same sentence: every successful business runs a cash flow forecast. The weekly grain is the part most businesses get wrong. Monthly averages delete the calendar — and the calendar is where cash problems live. A month that nets to break-even can contain a week that breaks you.
The five parts, in build order
1. Opening cash and a buffer. Sum every operating account on your start date — that's week 1's opening balance. Then set a minimum cash buffer: the floor you refuse to cross, typically one full payroll run plus rent. The buffer is the most important number in the model, because “when do I hit zero” is the wrong question — by the time you're near zero you've already missed payroll. The real question is what week do I cross the buffer.
2. The AR register — with realistic dates, not due dates. List every open invoice. For each one, record the week you actually expect the cash, which is rarely the due date. The client who pays Net-30 invoices on day 45 pays this one on day 45 too. This single discipline — forecasting receipts on realistic dates — is most of the difference between a forecast and a wish. If you don't know a customer's real paying behavior, look at their last three payments; the pattern is almost always stable.
3. The AP register — on the weeks you'll pay. Every bill, the week you plan to pay it. Mark which ones are deferrable without vendor damage — that list is your cheapest source of emergency cash, cheaper than drawing the line of credit, and you want it written down before the tight week, not discovered during it.
4. Recurring reality: payroll weeks, rent, and lumps. Payroll goes on the weeks payroll actually runs — if you pay semi-monthly, some months have two runs and the grid should show exactly where they land. Then the lumpy items: quarterly taxes, annual insurance, software renewals. These are the outflows monthly averages hide and week-by-week grids expose, and they are behind most “surprise” cash crunches that were never surprises.
5. The chain. Each week: opening cash + total in − total out = ending cash, which becomes next week's opening. Flag any week where ending cash crosses the buffer. That flagged date is the most valuable output of the entire exercise — a deadline with a cause attached, weeks before it arrives, while collecting one receivable or deferring three bills can still move it.
The Monday ritual (this is where forecasts live or die)
A 13-week forecast is not a document; it's a loop. Every Monday, three steps, about twenty minutes by hand:
Grade last week. Enter actual ending cash next to what you forecast. Don't just overwrite it — the miss is the information. Which invoice didn't arrive? Which bill landed early? Every miss teaches you a customer's real behavior or a vendor's real schedule, and next week's forecast gets sharper because of it.
Roll forward. Last week's actual becomes the new opening balance, week 2 becomes week 1, and a fresh week 13 appears at the horizon.
Re-date the registers. Update expected weeks on anything that slipped, add new invoices and bills, and re-read the buffer line. If the breach date moved closer, you want to know Monday morning — not at the bank.
Operators who hold this ritual describe the same outcome, and it's not a financial metric: they stop checking the bank balance ten times a day. Managing by bank balance is the most common cash system in small business and the most anxious one — the forecast replaces it with one honest look a week.
Where spreadsheet forecasts go to die
Every operator who builds this spreadsheet discovers the same three failure modes. First, it decays: the forecast is accurate the afternoon you build it and drifts from reality daily until the Monday ritual quietly stops happening — usually during exactly the busy stretch when you most need it. Second, it double-counts: the insurance bill sits in the AP register and in a recurring row, and now your tight week looks $28,000 worse than it is — or the reverse, and it looks better. Third, nobody grades it: without the actuals discipline, the forecast is never wrong because it's never checked, which means it's never trustworthy either.
A fractional CFO solves all three — for $5,000–$15,000 a month, usually rebuilding the model quarterly. The template above solves them for free if you hold the Monday discipline. And this is, transparently, the problem XPlor exists for: it builds this exact forecast from your books automatically, reconciles the double-counts, re-dates receivables from observed payment behavior, and grades itself against your actuals every Monday — the ritual, without the twenty minutes or the decay.
Start this Monday
Download the template, spend forty-five minutes on the registers, and read your buffer line. Whatever date it shows you, you now know something most businesses your size don't know about themselves. Hold the ritual for four Mondays and you'll have something rarer still: a forecast with a track record.