The 13-week cash forecast, explained for a subcontractor

A subcontractor can be profitable and still run out of cash. The work is paid for weeks or months after it is done, a slice of every invoice is held back as retainage, and payroll goes out every Friday regardless. The profit and loss statement will not warn you about any of that, because it records revenue when it is earned, not when the general contractor pays.

The tool that does warn you is the 13-week cash forecast: a week-by-week projection of the cash that will come in, the cash that will go out, and the balance left at the end of each week.

Why thirteen weeks

Thirteen weeks is one quarter. It is long enough to see a problem while there is still time to do something about it: chase a pay application, delay a purchase, talk to the bank about the line of credit. It is short enough that most of the numbers in it are known rather than guessed. You already know your payroll, your rent, your equipment payments and most of your supplier invoices for the next few weeks. Receipts are harder, which is where most of the work goes.

Receipts: by general contractor, not by job

For a subcontractor, the receipts side of the forecast is built from your open pay applications and your billing schedule, and it is most useful organised by who pays you.

Each general contractor has its own habits. One pays thirty days after the application is approved. Another pays when the owner pays them, which can mean sixty days or more. A third reliably disputes the first application on every job. Your receivables aging already contains this history. The forecast turns it into dates.

Three things need their own lines:

• Progress billings. The pay applications you expect to submit and the week you expect each to be paid, net of retainage.
• Retainage. Usually released at substantial completion or at the end of the job, and often later than the contract says. Retainage is money you have earned, and for many subcontractors it is the largest single receivable. Forecasting it separately stops it from inflating the near-term weeks.
• Change orders. Only approved ones. Pending change orders go in a note, not the forecast.

Disbursements: the fixed rhythm

The outflow side follows a rhythm you already live with:

• Payroll every Friday, or every other Friday, including payroll taxes and union or benefit contributions if you carry them.
• Suppliers on their terms. If your main supplier gives you thirty days and your general contractor takes sixty, the gap is financed out of your bank balance. The forecast shows how large that gap is each week.
• Equipment and vehicle payments, rent, insurance. Insurance deserves attention because it is often paid quarterly or in large instalments, which produces one heavy week.
• Owner draws and debt service. They are real cash and belong in the forecast, not in a separate conversation.

A few weeks of it

Here is the shape, with illustrative figures:

Week 4 is the one to look at. A single large pay application landing in week 3 makes the month look fine in total, but a quarterly insurance payment and a thin week of receipts leave the balance close to one payroll. Seen three weeks ahead, that is a phone call to a general contractor about an approved application, or a conversation with a supplier about timing. Seen on the Thursday, it is a problem.

Reading the forecast in the portal

In our client portal the forecast appears as a chart of the closing balance for each of the thirteen weeks, with the receipts and disbursements behind it available as a table. Three things are worth checking every time it updates:

1. The lowest week. Not the average and not the ending balance. The low point is the number that decides whether you need to act.
2. What moved since last time. A forecast that is re-run each period shows which receipts slipped. A general contractor whose payments keep slipping a week at a time is telling you something.
3. Actual against forecast. Last week’s forecast next to what really happened. If receipts are consistently late, the assumptions need changing.

The same forecast for an online brand

An e-commerce brand runs the same thirteen weeks with different lines. Receipts are payouts, not invoices: Shopify pays on business-day timing, net of fees and refunds, and Amazon pays one net number every 14 days, with fees, storage, advertising and reserves already taken out, as its settlement guides report.¹ Disbursements are led by purchase orders: a deposit when the order is placed, the balance before the goods ship, then freight and duties when they land, weeks before the first unit sells. Built from the PO schedule and the payout calendar, the forecast shows the week the inventory is paid for and the payouts have not caught up. That is the week to size the order or line up financing, not the week to discover it.

Which bands include it

The forecast is part of the controller engagement from band B upward. How often it is updated depends on the band:

On band A, Controller Essentials, the forecast is not included; it is one of the things that changes when you step up to Controller + Cash.

It is also only as good as the books behind it. A forecast that starts from an unreconciled bank balance, or from a receivables aging nobody has cleaned up, is precise and wrong. That is why it comes after the close, not instead of it.

Sources

1. Nova Analytics, “Amazon Settlement Report: How to Read and Reconcile It in 2026”, 2026. A vendor figure, reported rather than measured. ↑