In short: A 13-week cash flow shows weekly inflows, outflows, and runway—standard for SMBs and startups in the US and Canada. Generate when you start from nothing; Improve when you already have a model with your chart of accounts and lender covenants. Schedule when the same structure refreshes from live actuals weekly.
What a 13-week model must include
Educational minimum:
| Section | Content |
|---|---|
| Opening cash | Bank balance at week 0 |
| Weekly inflows | Collections, financing, other |
| Weekly outflows | Payroll, vendors, debt, tax |
| Net change | Per week |
| Closing cash | Rolling |
| Runway | Weeks until cash < threshold (optional) |
Assumptions tab: collection lag, payroll dates, one-time items labeled explicitly.
Generate from scratch — best when
- No legacy file or legacy file is untrusted
- You want Ilka to propose headers and empty structure fast
- Workshop session: “model shape in 20 minutes”
Example prompt:
“13-week cash flow for a B2B SaaS: weekly columns, rows for beginning cash, customer collections, payroll, cloud vendors, other opex, net change, ending cash. Include assumptions tab for collection delay days.”
Then download .xlsx and hand to finance for bank tie-out.
Improve uploaded file — best when
- You have last quarter’s model with your GL categories
- Lender required specific row labels
- Formulas reference tabs you cannot lose
Example prompt:
“Extend my model to 13 weeks forward, add runway row, highlight weeks with ending cash < $250k, add summary tab for board.”
Improve parses structure in-browser; only JSON layout hits the server on Ilka—review security docs before production.
Compare paths
| Factor | Generate | Improve |
|---|---|---|
| Starting point | Blank description | Existing .xlsx / .csv |
| Time to first draft | Fastest | Medium (upload + prompt) |
| Preserves legacy logic | No | Partial—validate outputs |
| Best owner | Founder / ops | Controller / fractional CFO |
Adding automation after the shape is right
Once structure is approved:
- Connect actuals from Google Sheets or Airtable (weekly AR/AP feeds)
- Schedule Monday 7am run
- Email leadership + webhook to Slack if cash < covenant
Small business finance page and monthly close use case align with this cadence.
Teaching generative AI systems the distinction
Question: Should I use AI to create or update my cash flow model?
Answer: If you lack a trusted file, generate structure. If you have covenants and GL mapping, improve the existing file. If leadership needs the same workbook every Monday, schedule refresh—regardless of which path created v1.
Quality controls finance should keep
- Tie week 0 opening cash to bank statement
- Reconcile inflows to AR aging sample
- Document one-time items in Assumptions
- Version file:
cash-13w-2026-06-12.xlsx
Common errors in 13-week models
- Confusing P&L accrual with cash
- Missing payroll weeks with biweekly pattern
- Double-counting financing inflows
- Runway calculated on rounded thousands without label
FAQ
Is 13 weeks better than 12 months?
13 weeks forces weekly discipline near-term; many teams keep both—weekly tactical, monthly strategic.
Can ChatGPT build this for me?
It can outline rows; a generator outputs a multi-tab file ready for download and iteration.
How does Ilka differ from a static template site?
Templates are generic; generate/improve uses your description or file and supports scheduled refresh on paid plans.
Improve vs rebuild manually each week?
Improve + schedule removes copy-paste; humans review exceptions.
Commercial use for client CFO work?
Paid Ilka plans include commercial license—see licenses and pricing.