What if you could see a cash shortfall three months before it happened? That’s exactly what a 13-week cash flow forecast does. It’s one of the simplest and most powerful tools a business owner can use, and you don’t need to be an accountant to build one.
What Is a 13-Week Cash Flow Forecast?
It’s a week-by-week projection of the cash coming into and going out of your business over the next quarter (13 weeks). It focuses only on actual cash movements, not on profit.
Why 13 weeks? It’s long enough to spot problems while you still have time to act, and short enough to stay accurate.
Why It Matters
A cash flow forecast helps you:
- Spot shortfalls early, while you still have options
- Time big payments, such as equipment, taxes, or bonuses
- Plan payroll with confidence
- Talk to your bank with credible numbers when you need financing
- Make decisions about hiring, purchases, or growth based on facts
How to Build One in 5 Steps
Step 1: Start With Your Opening Cash
Enter the cash in your bank accounts at the start of Week 1.
Step 2: List Your Cash Inflows by Week
Estimate when money will actually arrive:
- Customer payments, based on when customers really pay, not when you invoice
- Cash sales
- Loans or capital injections
- Tax refunds or other income
Step 3: List Your Cash Outflows by Week
Estimate when money will actually leave:
- Payroll and source deductions
- Rent and utilities
- Supplier and inventory payments
- Loan payments (principal and interest)
- GST/QST remittances
- Insurance, software, and subscriptions
- Owner withdrawals
- One-time purchases
Step 4: Calculate Your Closing Cash
For each week, use this formula:
Opening Cash + Inflows − Outflows = Closing Cash
Each week’s closing cash becomes the next week’s opening cash.
Step 5: Update It Every Week
Replace estimates with actual figures, then roll the forecast forward one week so you always see 13 weeks ahead.
A Simple Example
| Week 1 | Week 2 | Week 3 | |
|---|---|---|---|
| Opening cash | $40,000 | $33,000 | $41,000 |
| + Inflows | $25,000 | $30,000 | $18,000 |
| − Outflows | $32,000 | $22,000 | $35,000 |
| Closing cash | $33,000 | $41,000 | $24,000 |
If you know you need at least $25,000 on hand, Week 3 is a warning sign, and you can see it now. You could follow up on overdue invoices, delay a non-urgent purchase, or arrange short-term financing.
Tips for an Accurate Forecast
- Be conservative: estimate inflows on the low side and outflows on the high side.
- Use real payment patterns: if a customer usually pays in 45 days, plan for 45 days, not 30.
- Don’t forget irregular payments: annual insurance, quarterly tax instalments, and seasonal costs.
- Set a minimum cash buffer and highlight any week that falls below it.
Frequently Asked Questions
What is the difference between a cash flow forecast and a budget?
A budget plans revenue and expenses, usually over a year. A cash flow forecast tracks when cash actually moves in and out, week by week.
How often should I update my forecast?
Every week. A forecast is most useful when it’s kept current.
Can I build it in Excel?
Yes. A simple spreadsheet works well. Many cloud accounting tools also include forecasting features.
Let AccoClariT build and maintain your forecast for you. Forward-looking planning tools like this are part of our Momentum support level. Book your free 45-minute consultation.