Timing kills, not economics
A business can be profitable on paper and dead in practice: revenue booked in March, collected in June, payroll due in April. Cash flow forecasting exists to catch exactly that gap - early enough that your options are 'invoice harder, delay a purchase, draw a line' instead of 'emergency loan'.
Why 13 weeks
Thirteen weeks is a quarter plus a breath. Long enough to see the next tax payment, rent cycle, and every payroll; short enough that week-by-week estimates stay honest. Beyond 13 weeks you're modeling; inside it you're observing.
- 13
- weeks - one quarter of visibility
- 15 min
- weekly update once it's running
- 1
- number that matters: your lowest future cash point
The structure: three rows of truth
- Cash in - customer receipts timed by when they actually pay (their history, not your due dates), plus any other inflows.
- Cash out - payroll, rent, suppliers, tax remittances, loan payments, timed by their real dates.
- Running balance - opening cash plus each week's net. The line you actually read.
The honesty rule
Forecast receipts by customer behavior, not invoice terms. If Acme pays Net 30 invoices in 45 days, week 7 revenue lands in week 9 cash. The forecast is for you - flattering it defeats the purpose.
The 15-minute weekly ritual
- 1
Roll the week
Last week becomes actuals; week 14 becomes visible. The forecast always looks 13 weeks ahead.
- 2
Correct the misses
Which receipts slipped? Move them, and note the customer - repeat slippers get shorter terms.
- 3
Read the low point
Find the minimum balance and its date. That's your entire cash strategy in one number.
- 4
Act if it's red
Below your comfort floor? You have 8+ weeks of options: collect, defer, cut, or fund - in that order.
Why 13 weeks specifically, and not a shorter or longer forecast?
13 weeks is one full quarter of visibility - long enough to see the next tax payment, rent cycle, and every payroll run, short enough that week-by-week estimates stay honest. Beyond 13 weeks you’re modeling assumptions; inside it you’re observing near-term reality.
Should I forecast receipts based on invoice due dates?
No - forecast by when customers actually pay, based on their real payment history, not your stated terms. If a customer pays Net 30 invoices in 45 days on average, model week 9 cash, not week 7. The forecast is for you; flattering it defeats the purpose.
How long does it take to maintain a rolling cash flow forecast?
About 15 minutes a week once it’s set up: roll last week into actuals, correct any receipts that slipped, and read your lowest projected cash point and when it lands. That one number is effectively your entire near-term cash strategy.
The forecast never has to be right. It has to be early.
What is slow payment costing you?
Days recovered
25
Cash unlocked once
41,667
Financing saved / year
5,000
Illustrative only - cash unlocked = daily revenue × days recovered; financing saved assumes that cash otherwise carries your stated cost of money.
Resources
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