What it is, why the number is 13, how to build one that holds up, and the mistakes that quietly ruin the ones that do not.
It projects the cash coming into and going out of your business over the next 13 weeks, one fiscal quarter. Unlike an annual budget or a monthly forecast, the week-by-week view is granular enough to manage day-to-day liquidity and make operating decisions on real numbers.
It uses the direct method: actual cash receipts and payments, not accrual entries. That is what makes it usable. You are looking at the money, on the day it moves.
A rolling, week-by-week projection of all cash in and all cash out, updated weekly so it never goes stale.
The number is not arbitrary. It sits at the point where accuracy and usefulness still overlap.
Lines up with the reporting cycles and board meetings you already run.
Close enough to stay accurate, far enough out to still be worth planning against.
Enough lead time to arrange credit, chase receivables, or move a payment before the gap arrives.
Update weekly and the window slides forward, so you always see the next quarter.
Profitable companies fail when they run out of cash at the wrong moment. The forecast is the early warning.
Spot the gap weeks in advance and you have time to arrange financing, accelerate collections, or defer a payment. That is the difference between a plan and a panic.
When you know a surplus is coming, you can pay down debt, earn interest on it, or fund something that grows the business instead of letting it sit.
Hiring, equipment, expansion. Knowing your cash position turns those from gut calls into decisions you can defend.
Banks, investors, and boards want evidence you know where the cash is going. A maintained forecast is that evidence.
It started with distressed companies and turnaround work. It is now standard practice at every size.
Your starting point for the week. In a rolling forecast it is last week's closing balance.
Customer collections, new sales and deposits, other income such as interest or asset sales, and financing proceeds.
Payroll and benefits, vendor payments, rent and utilities, loan payments, taxes, and capital spending.
In minus out for the week. Tells you whether the week generated cash or consumed it.
Opening balance plus net cash flow. This is the number that matters.
Consistency is what makes a forecast accurate
Roll the forecast forward each week: add a new week 13 and lock actuals for the week that just closed. That keeps it fresh and builds the record you need for variance analysis.
Replace projections with what really happened
Lock in actual cash movements for completed weeks. It creates accountability and shows you where your projections held up and where they did not.
Prepare for more than one outcome
Bear, base, and bull cases show the range you are actually operating in. Plan for the downside while you work toward the upside.
Forecasting is a team sport
Sales knows what is landing. Operations knows vendor timing. HR knows payroll. The best forecasts combine financial data with operational knowledge.
The gap between forecast and actual is the lesson
Understanding why you were off, whether timing, a missing transaction, or a bad assumption, is what makes next week's forecast better.
Less manual work, fewer errors
Connect the forecast to your banking and accounting systems. Automatic statement ingestion and categorization saves hours every week.
Recording revenue when it is earned rather than when the money lands defeats the point. Track when cash moves.
Customers pay on their historical pattern, not on your terms. Model the pattern.
If you recategorize week to week, trends disappear and variance analysis means nothing.
A forecast that is not updated weekly goes stale fast. The value is in the discipline.
Tracking every minor expense line adds maintenance without adding insight. Group the small stuff.
Debt payments, tax deposits, and capital spending move real money. Do not model operating cash only.
Monthly forecasts hide timing. Inside a single month you might owe payroll on the 15th and expect a large customer payment on the 30th. A monthly view never shows that gap. Weekly precision is what lets you manage the timing of payments and receipts.
Initial setup runs from a few hours to a few days depending on your data. Once it exists, weekly updates take one to three hours by hand, or 15 to 30 minutes with automatic data feeds and categorization.
Excel works for simple situations and gets error-prone as complexity grows. Dedicated software gives you bank connections, categorization rules, variance tracking, and scenario modeling without the spreadsheet gymnastics.
Aim for 90 to 95 percent in the first two or three weeks, where visibility is high. Weeks 4 to 8 typically land at 80 to 85 percent, and weeks 9 to 13 at 70 to 80 percent. What matters is tracking your accuracy and improving it.
Consolidate them into one view of total cash, and still track individual balances so you never overdraw one account while another sits full. Minimum balance requirements per account are worth including.
A rolling forecast keeps a constant 13-week forward view: each week you drop the completed week and add a new week 13. A static forecast covers a fixed period and shrinks as time passes. Rolling is preferred because the horizon never shortens.
TreoCast reads your bank statements and fills in the 13 weeks. About 15 minutes for a first forecast.