What is a good 13-week cash flow forecast example for a small business?

A week cash flow forecast example is easiest to understand when you see the actual numbers laid out, so this article walks through a complete 13-week rolling cash flow forecast for a fictional small business, explains how each line is built, and shows you how to adapt it to your own company. The 13-week format is the standard used by turnaround professionals, lenders, and accountants like CliftonLarsonAllen, who recommend that every manufacturer maintain a rolling 13-week forecast as a baseline cash management discipline. The reason 13 weeks specifically is that it covers one full quarter, it is short enough that weekly estimates are reasonably accurate, and it is long enough to reveal a cash crunch before it arrives rather than after.

What a 13-Week Cash Flow Forecast Actually Is

Also worth reading: Can AI cashflow transparency for SMBs turn small business finance into a savings engine? · Can AI Be Your Small Business's Personal Financial Advisor? · How Should a Small Business Budget for an AI Pilot in 2026?

A 13-week cash flow forecast is a spreadsheet or tool that projects your cash position at the end of each of the next 13 weeks. Unlike a monthly budget or an accrual-based income statement, it tracks only cash moving in and out of your bank account. Revenue you have invoiced but not collected does not count. Rent you owe but have not paid does not count. Only cleared and expected cash matters.

The structure is simple: each week is a column, and the rows are your categories of cash in and cash out. At the bottom of each column you calculate three figures: total cash in, total cash out, net cash flow (in minus out), and ending cash (last week's ending cash plus this week's net flow). The ending cash line is the one that matters most, because it tells you whether you will clear your payroll, your tax obligations, and your minimum bank balance requirements in any given week.

Because it is a rolling forecast, every week you drop the oldest week, add a new week thirteen weeks out, and update your actuals. This is what Oracle NetSuite and other finance software vendors describe as the core of rolling forecast best practice: the forecast never expires, so you always have a full quarter of visibility ahead of you. A forecast built once in January and never updated is worse than no forecast, because it creates false confidence.

A Complete Week Cash Flow Forecast Example

Here is a worked example for a small manufacturing or wholesale business with about $80,000 in monthly revenue, a 45-day average collection cycle, and a $25,000 opening cash balance. The numbers are illustrative but the proportions are realistic for an SMB carrying inventory and offering net-30 to net-45 terms to customers.

Notice several things about this example. First, the business is roughly cash-neutral over the quarter: it starts at $25,000 and ends at $27,100, but it dips as low as $16,900 in week five. If this company had a $15,000 minimum operating balance or a loan covenant requiring $20,000 in liquidity, weeks one through seven would be a problem, and the forecast would have flagged it six to seven weeks in advance, which is exactly enough time to arrange a line of credit draw, accelerate collections, or delay a discretionary purchase.

Second, the cash out column is lumpy on purpose. Weeks four and nine are heavier because of semi-monthly payroll, quarterly estimated tax payments, or inventory supplier payments that fall due. A monthly budget smooths these out and hides them; a weekly forecast exposes them. Most small business cash crises are not caused by unprofitability but by timing mismatches, and this table is the tool that reveals timing.

How to Build Each Line: Cash In

The cash in section should be built from your accounts receivable aging report, not from your sales forecast. This is the single biggest mistake beginners make. If your customers pay on average 40 days after invoice, then the cash arriving this week was invoiced roughly six weeks ago. Pull your AR aging, sort invoices by expected payment date based on each customer's actual payment behavior, and place those amounts in the appropriate week.

For a business with ten large customers, forecast each customer individually, because concentration risk matters enormously. If one customer represents 30 percent of collections and they pay in 60 days instead of 45, your entire forecast shifts. For businesses with many small customers, group them into two or three payment-behavior tiers and apply average collection days to each tier. Add a separate line for cash sales and card payments, which typically clear in one to three business days, and a line for expected new collections from work being invoiced during the forecast period itself.

Be conservative. A common practice is to apply a collection haircut, for example assuming 90 percent of expected collections arrive on time and the remaining 10 percent slip one to two weeks. If your forecast only works when every customer pays exactly on schedule, it is not a forecast, it is a wish.

How to Build Each Line: Cash Out

Cash out categories for a typical SMB include payroll and payroll taxes, rent or mortgage, supplier and inventory payments, loan payments, insurance, utilities, software subscriptions, professional fees, marketing spend, owner draws or distributions, and tax payments. The key discipline is to schedule each item into the specific week it will actually leave the account, not the week it is incurred.

Payroll is usually the most predictable line: if you run biweekly payroll, it hits in alternating weeks and should appear in six or seven of the thirteen columns. Supplier payments should come from your accounts payable aging, using each vendor's actual terms. Quarterly tax payments, insurance premiums, and annual renewals are the lines people forget; mark them on a calendar and place them in the correct week, because a $12,000 quarterly tax payment landing in an otherwise thin week is a classic cause of avoidable overdrafts.

Also separate fixed from discretionary outflows. Rent and payroll are committed; a planned equipment purchase, an extra marketing push, or an owner distribution can be moved. When your forecast shows a low week, the discretionary lines are your levers. This is why the forecast should list them on separate rows rather than lumping everything into one 'expenses' line.

Spreadsheet vs. Dedicated Software: Comparing Your Options

Most businesses start in a spreadsheet, and for many that is genuinely fine. But spreadsheets have known failure modes: broken formulas, stale data, no audit trail, and heavy dependence on one person who understands the file. Here is an honest comparison.

The honest critique of dedicated tools is that many of them simply automate the import step while still requiring you to categorize and adjust, so the time savings can be smaller than marketing suggests. The honest critique of spreadsheets is that they silently rot: the week someone forgets to update the AR aging is the week the forecast lies to you. AI-assisted tools attempt to close this gap by learning each customer's actual payment behavior from history and projecting collections automatically, which is useful, though you should always be able to see and override the assumptions. Transparency in how a projection was built matters more than the projection itself, because a black-box number you cannot interrogate is not a management tool.

Common Mistakes That Ruin a Week Cash Flow Forecast

The first mistake is forecasting on an accrual basis. If you record revenue when invoiced and expenses when incurred, your forecast will show profits in months when your bank account is empty. Cash forecasting means cash timing only, full stop.

The second mistake is using average collection periods for every customer. A blended 40-day average hides the fact that your biggest customer pays at 70 days and your small customers pay at 25. Forecast by customer or by tier.

The third mistake is ignoring the opening balance reality. Your forecast must start from actual cleared bank balances across all accounts, including any line of credit drawn and any undeposited funds. Businesses with multiple accounts frequently forecast one account and forget the transfer timing between them.

The fourth mistake is not updating it. A 13-week forecast that is refreshed weekly takes 20 to 40 minutes once the template exists. One refreshed monthly takes the same time but delivers a fraction of the value, because by the time you see a problem three weeks out, your options have collapsed to expensive ones.

The fifth mistake is optimism bias in the cash in column. Compare your forecasted collections to actual collections each week and track the variance. If you over-forecast collections by more than about 10 percent for three consecutive weeks, your assumptions are wrong and need rebuilding, not adjusting.

When to Act on What the Forecast Shows

The forecast is only useful if you set thresholds in advance and act on them mechanically. A practical framework: if projected ending cash in any week falls below one month of fixed operating costs (for the example above, roughly $20,000), that is an amber flag, and you begin accelerating collections and deferring discretionary spend. If it falls below two weeks of fixed costs (roughly $10,000 here), that is a red flag, and you should be talking to your bank about your line of credit, prioritizing payables by consequence, and cutting non-essential outflows the same week.

Timing matters because options degrade as the horizon shortens. Twelve weeks out, you can renegotiate supplier terms, run a collection push, time a tax payment, or delay a hire. Three weeks out, your realistic options are a credit line draw, an emergency receivables factoring arrangement at a discount, or asking your best customers to pay early, sometimes with a 1 to 2 percent early-payment incentive. All of those cost money or goodwill that earlier action would have avoided. This is why the CFO-focused press keeps returning to cash visibility: the businesses that fail in a downturn are usually not the unprofitable ones but the ones that ran out of weeks.

If you carry debt, check whether your lender requires minimum liquidity or fixed-charge coverage covenants. Your 13-week forecast is the earliest warning you will get that a covenant test is at risk, and lenders respond far better to a borrower who flags a problem at week twelve with a plan than one who reports a breach after the fact.

Adapting the Example to Your Business

Service businesses with net-15 or net-30 terms and no inventory can simplify the example considerably: cash in is mostly collections from invoices, and cash out is dominated by payroll and subcontractors. Their forecast will be smoother and their danger weeks are usually the ones with two payroll runs and a quarterly tax payment stacked together.

Product and manufacturing businesses need the inventory purchase line modeled carefully, because inventory spend precedes revenue by weeks or months. If you buy $40,000 of materials in week two to fulfill orders that collect in week ten, your forecast must show that gap honestly. Seasonal businesses should extend the forecast horizon or run a 26-week version during the off-season, because a 13-week window in the slow months tells you only that cash is declining, not when it recovers.

Whatever your model, the habit loop is the same: update actuals weekly, roll the horizon forward, compare forecast to actual, and adjust your assumptions based on the variance. Businesses that do this for 13 consecutive weeks typically find their forecast accuracy within 5 to 10 percent, which is accurate enough to make every timing decision that matters. The forecast is not about predicting the future perfectly; it is about never being surprised by a week you could have seen coming twelve weeks earlier.