THE 13-WEEK CASH FLOW FORECAST FOR SUBS.
A 13-week cash flow forecast is a rolling, week-by-week projection of cash in and cash out over the next quarter. For subcontractors it is the single tool that turns "profitable but always short" into a number you can see coming, because it maps retention, pay-app timing, payroll, and material against the bank balance week by week.
A profit and loss statement tells you whether the work made money. It does not tell you whether you can make payroll on the 15th. Those are different questions, and for a subcontractor the second one is the one that ends businesses. The 13-week cash flow forecast answers it. It lays out every expected dollar coming in, by pay app and retention release, against every dollar going out, payroll, material, overhead, debt, week by week for the next quarter. Thirteen weeks is one quarter, far enough to see a shortfall while there is still time to act, close enough to forecast with real numbers instead of guesses. This page explains what it is, why profit and cash diverge for subs, and how to build and run one.
WHAT A 13-WEEK FORECAST IS.
A 13-week cash flow forecast is a rolling, weekly projection of expected cash receipts and disbursements over the coming quarter. Every week gets its own column: cash expected in, cash committed out, and the projected bank balance at the end of that week.
It rolls. Each week you drop the week that just closed and add a new week 13 out, so you always have a full quarter of visibility ahead. Thirteen weeks is deliberate: one quarter is long enough to see a payroll you cannot cover three weeks before it lands, and short enough that the numbers are real commitments, not estimates.
PROFIT AND CASH ARE NOT THE SAME.
A subcontractor can be profitable on every job and still run out of cash, because the money is earned long before it arrives. Retention is held until closeout. Pay apps are paid 45 to 90 days after the work. Material and payroll go out now. The profit is real; the cash is just not here yet.
A profit and loss statement cannot show that gap, because it records revenue when it is earned, not when it is collected. The 13-week forecast is built on collection timing, not earning timing, which is exactly why it catches the squeeze a P&L hides. The Construction CFO has watched a civil contractor go from 3am payroll math to a $300,000 cash floor once the forecast made the gap visible.
THE LINES THAT MAKE IT WORK.
A 13-week forecast for a subcontractor is built from real commitments, not averages:
KEEP IT LIVE, NOT A ONE-TIME FILE.
A forecast you build and forget is wrong by week two.
Set the 13 weeks up once with your real commitments, then update it every week: actuals for the week that closed, revised dates for pay apps and retention, and a fresh week 13 on the end. Fifteen minutes a week keeps it accurate. The whole value is that it stays current with how the GCs are actually paying.
The number that matters is the low point.
A quarter can net positive and still have a week where the bank goes negative. The forecast exists to find that week. When you see a shortfall three or four weeks out, you have time to accelerate a pay app, delay a non-critical purchase, or arrange a draw, instead of discovering it the morning payroll is due.
The forecast is short range; the CEO report is the trend.
The 13-week forecast handles the next quarter of cash. The monthly CEO report handles the longer trend in margin, overhead, and net profit. Run both. The forecast keeps you solvent week to week; the report keeps you profitable quarter to quarter.
SEE THE SQUEEZE BEFORE IT ARRIVES.
The 13-week cash flow forecast is the difference between knowing on Monday that week six is tight and finding out on a Friday that you cannot make payroll. For a subcontractor, that visibility is worth more than another won bid.
The Construction CFO builds and maintains this forecast as part of CFOS for commercial subcontractors doing $1M to $12M, alongside job costing and a monthly CEO report.
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