The 13-week cash flow forecast, explained

The practice is usually called 13-week cash forecasting, and the document it produces is the 13-week cash flow forecast. Weekly is the cadence. Thirteen weeks is the window. Everything below is that one grid: what goes in it, how to read it, what it looks like, and who is going to ask you for it.

What it is called elsewhere

The same document travels under a lot of names, which is why it is hard to search for. They are not different methods, and if someone hands you one of these expecting another, nothing about the work changes.

Weekly cash forecast, or weekly cash flow forecast. The same grid named after its cadence rather than its length. If somebody asks for a weekly cash flow and gives no window, they almost always mean a quarter.

Rolling 13-week cash flow. The same grid, with the emphasis on the maintenance: each week drops off the front and a new week is added at the back, so the window is always a full quarter ahead. Rolling is not an option, it is the only version that stays true.

Thirteen-week cash flow model. Usually means the spreadsheet itself rather than the output, and often implies scenarios sitting behind it: what the low week becomes if a large receipt slips a fortnight.

Weekly cash flow statement. A slightly unhelpful name, because a cash flow statement in accounting is a backward-looking report and this is a forward-looking plan. Same grid, different direction in time.

12-week cash flow. One fewer column. Thirteen weeks is preferred because it maps to a calendar quarter exactly, so the forecast lines up with the quarter your bank, your board and your tax calendar already use.

Why weekly, not monthly

Months are round and cash is not. Payroll lands twice or three times, tax weeks arrive on their own schedule, and one big customer payment can move a whole month from red to black. A monthly cash summary averages all of that into a number that looks fine. The weekly view shows the dip the average hides. The slower question, whether the year is still on track, runs on its own rhythm, and quarterly forecasting is that discipline.

What goes in

Opening cash. Real balances, reconciled, not the accounting cash line.

Receipts by week. When customers actually pay, not when you invoice them. If a customer pays in 45 days, their money belongs six weeks out, whatever the invoice says. If the business has a season, this is the line it lands on, and reading your seasonal shape tells you which weeks to plan around before the quarter starts.

Disbursements by week. Payroll, rent, suppliers, loan payments, taxes, owner draws. The recurring ones are easy; the quarterly and annual ones are the ambush, so they go in the week they hit.

A minimum cash line. The balance you refuse to fall below. Without it the forecast is a chart; with it every week is a pass or a fail.

How to read it

Find the lowest week first. That week is the whole document. If it sits above your minimum, breathe and check direction. If it sits below, you have a decision with a date on it, and the earlier you are reading this, the cheaper the decision is. If your first question is the backward one, whether last month actually made money, the free month check answers it in two minutes; then come back here for the forward view.

A composite example, the kind we see often: a services company runs the forecast and week 9 dips under the minimum. Nothing is wrong today. But payroll lands in week 9 and the two receipts that cover it land in week 10. Seen from week 2, the fix is small: one invoice pulled forward with a deposit, one supplier payment shifted a week. The dip never happens. Found on the Friday of week 9, the same problem is a scramble and a phone call to the bank.

A worked example

Here is the shape, using the week 9 problem above. Five of the thirteen columns are shown so it fits on a phone; the real grid runs the full quarter and the rows never change. Figures are an illustration, not a client.

The headroom row is the only row you have to read. It is closing cash less the floor, so anything in brackets is a week that fails. Week 9 comes in 29 below the line, and every other week passes comfortably, which is exactly why the monthly view missed it: across the month the average is fine.

The cause is visible in the same column. Disbursements jump in week 9 because payroll lands there, and receipts are thin because the two large payments arrive in week 10. The business is not short of money. It is short of money on a Tuesday.

That is the whole reason to keep the grid. The problem has a date, so the fix can be small and boring: one invoice pulled forward with a deposit, one supplier payment moved a week, and week 9 closes above the line without anybody calling the bank.

Who is going to ask you for one

Most owners meet this document because somebody outside the business asked for it, usually at short notice, and it is worth knowing which conversation you are in.

Your bank or lender. Renewals, covenant conversations and any request to increase a facility tend to come with a request for forward cash. A lender is checking one thing: whether you can see a problem before they do.

A buyer, or their adviser. In a sale process the weekly view is how a buyer tests whether the business runs on rhythm or on the owner's memory. It is also how working capital gets argued about, so it is worth having yours before anybody asks.

A turnaround or restructuring adviser. This is the setting the format is most associated with, and where its weekly discipline comes from. If a restructuring professional is involved, the 13-week is usually the first document requested and it is refreshed every week without exception. The standard their profession holds it to has its own page.

A board, or an investor. Boards ask for the low week and the date of it. Nothing else on the cash page usually gets discussed.

The pattern worth noticing: in every one of those rooms the forecast already exists or it does not, and building one under pressure is when the numbers are least trustworthy. It is a cheap document to keep and an expensive one to produce in a hurry.

Keeping it honest

Every week, actuals replace estimates, the window rolls forward one week, and a line notes what changed. A forecast that is not maintained weekly decays into fiction in about a month.

The forecast ships inside every ClarIQ monthly close, updated on rhythm and tied to your books. It pairs with the monthly close and lands beside the monthly memo. The sample memo shows the cash view in context. And if your real question is why the books say profit while the account drains, start with where the money goes when you are profitable but out of cash.

Published July 19, 2026. Last reviewed August 29, 2026.