13-week rolling cash flow modeler
Short answer
A 13-week cash flow forecast projects actual cash receipts and payments week by week for the next quarter. Ending cash each week is the opening balance plus collections, minus supplier payments, payroll, rent and tax remittances, so you can see a cash shortfall before it happens.
Model the next 13 weeks
Ending cash, week 13
$312,379
Lowest cash (week 1)
$235,150
13-week net cash flow
$62,379
Weeks below minimum
0
Stress test
| Week | W1Nov 8 | W2Nov 15 | W3Nov 22 | W4Nov 29 | W5Dec 6 | W6Dec 13 | W7Dec 20 | W8Dec 27 | W9Jan 3 | W10Jan 10 | W11Jan 17 | W12Jan 24 | W13Jan 31 | Total |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Opening cash | $250,000 | $235,150 | $280,300 | $265,450 | $275,636 | $260,786 | $305,936 | $291,086 | $301,593 | $286,743 | $331,893 | $317,043 | $362,193 | $250,000 |
| Collections from customers | $102,900 | $102,900 | $102,900 | $102,900 | $102,900 | $102,900 | $102,900 | $102,900 | $102,900 | $102,900 | $102,900 | $102,900 | $102,900 | $1,337,700 |
| Total receipts | $102,900 | $102,900 | $102,900 | $102,900 | $102,900 | $102,900 | $102,900 | $102,900 | $102,900 | $102,900 | $102,900 | $102,900 | $102,900 | $1,337,700 |
| Supplier payments (AP) | ($57,750) | ($57,750) | ($57,750) | ($57,750) | ($57,750) | ($57,750) | ($57,750) | ($57,750) | ($57,750) | ($57,750) | ($57,750) | ($57,750) | ($57,750) | ($750,750) |
| Payroll | ($60,000) | – | ($60,000) | – | ($60,000) | – | ($60,000) | – | ($60,000) | – | ($60,000) | – | ($60,000) | ($420,000) |
| Rent and overhead | – | – | – | ($25,000) | – | – | – | ($25,000) | – | – | – | – | ($25,000) | ($75,000) |
| GST/HST remittance | – | – | – | ($9,964) | – | – | – | ($9,643) | – | – | – | – | ($9,964) | ($29,571) |
| Total disbursements | ($117,750) | ($57,750) | ($117,750) | ($92,714) | ($117,750) | ($57,750) | ($117,750) | ($92,393) | ($117,750) | ($57,750) | ($117,750) | ($57,750) | ($152,714) | ($1,275,321) |
| Net cash flow | ($14,850) | $45,150 | ($14,850) | $10,186 | ($14,850) | $45,150 | ($14,850) | $10,507 | ($14,850) | $45,150 | ($14,850) | $45,150 | ($49,814) | $62,379 |
| Ending cash | $235,150 | $280,300 | $265,450 | $275,636 | $260,786 | $305,936 | $291,086 | $301,593 | $286,743 | $331,893 | $317,043 | $362,193 | $312,379 | $312,379 |
Outflows are shown in parentheses. Weeks that end below $0 are shaded red. Sales and purchases exclude GST/HST; collections and supplier payments include it.
How does the model time each cash flow?
Sales and purchases are spread evenly across each day, then collected at 30, 60 and 90 days and paid after your AP days, so a 30-day lag lands on the right calendar week.
Payroll runs every two weeks, rent falls in the week containing the 1st of each month, and net GST/HST is remitted by the end of the month after each period.
The stress test assumes that, from week 1, customers pay the chosen number of days later, including on invoices already outstanding. That opens a gap in collections at the start.
How do I build a 13-week cash flow forecast?
- 1
Start from today's bank balance
Week 1 opens with the cash you actually have, not book cash.
- 2
Forecast collections from your AR curve
Apply the share of sales you collect at 30, 60 and 90 days to past and projected sales, including the GST/HST customers pay.
- 3
Schedule supplier payments
Shift purchases by your AP payment days, then add payroll on each pay date and rent on the 1st of each month.
- 4
Add tax remittances
Remit net GST/HST by the end of the month after each reporting period (monthly or quarterly).
- 5
Roll the balance forward and stress it
Ending cash = opening cash + receipts − disbursements. Slow collections or cut sales to find the weeks that need financing.
Frequently asked questions
What is a 13-week cash flow forecast?
A week-by-week projection of cash receipts and payments for the next quarter. Lenders, boards and turnaround advisers use it because it shows exactly which weeks are tight, which a monthly forecast can hide.
When is GST/HST due for monthly and quarterly filers?
For monthly and quarterly filers, the return and payment are due one month after the end of the reporting period. Annual filers who are individuals with business income have different dates.
Why use the direct method?
The direct method lists actual cash in and out (collections, supplier payments, payroll, rent, tax), so it matches the bank account. The indirect method starts from profit, which is better for reporting than for managing weekly liquidity.
Where do these numbers come from?
All amounts are your assumptions. Math uses decimal arithmetic rounded to the cent each week, so every column rolls forward exactly. Check your own GST/HST filing frequency and due dates with the CRA.