Small Business 13-Week Cash Flow Forecaster

You help an owner, founder or bookkeeper see the next quarter of cash week by week: what comes in, what goes out, where the balance bottoms out, and what to do before it gets there. Profit and loss says whether the business makes money; the 13-week forecast says whether it can pay salaries on the 1st. You keep the inputs as a CSV anyone can edit, count invoices when customers really pay (not when they are due), weight uncertain deals, run a stress case next to the base case, and turn the low point into a short list of actions. ## Files in this skill - `scripts/cashflow13.py` - reads the CSV, expands every schedule into dated payments in the horizon, applies customer lateness and probabilities, rolls the balance week by week in cents for a base and a stress case, and reports the low point, the first week below the buffer, the gap, credit line cover, the recurring run-rate and runway, flexible payments before the low point, the invoices that matter, customer concentration and one week's detail (Python 3.8+ standard library only) - `references/forecast-method.md` - the CSV format, schedules, timing rules, the base and stress cases, and how to keep the forecast honest week after week - `references/cash-levers.md` - what to do about a gap: collect, defer, cut, finance, in order of cost and speed - `templates/cash-flow-brief.md` - the one-page brief to hand back - `examples/studio-cashflow.csv` - a 5-person design studio: retainers, invoices on 30/45-day terms, an overdue invoice, an 80% milestone, a 40% pitch, biweekly salaries, VAT, tax prepayment, a year-end bonus and a 20,000 EUR credit line - `examples/studio-forecast.md` - the real output of the forecaster on that file - `examples/cafe-winter.csv` - a cafe with weekly takings and suppliers, a January dip, quarter-day rent and a VAT bill in the same month ## Workflow ### 1. Collect the inputs Ask for: cash in the bank today (all accounts the business can use, minus cheques not yet cleared), the minimum balance the owner wants to keep (one payroll plus a month of fixed costs is a common floor), any undrawn credit line, and the start Monday. Then list every receipt and payment for the next 13 weeks: recurring income (retainers, subscriptions, takings), open invoices with invoice date and terms, expected new work with an honest probability, payroll and payroll taxes, rent, loans, suppliers, software, tax and VAT dates, annual bills, planned purchases and bonuses. Ask how late customers usually pay and which payments could move (`flex=yes`). Use the bank statement and the accounting system's aged receivables/payables lists, not memory. ### 2. Run the forecaster ``` python3 scripts/cashflow13.py examples/studio-cashflow.csv python3 scripts/cashflow13.py forecast.csv --opening 41250 --min 15000 python3 scripts/cashflow13.py forecast.csv --stress-cut 30 --stress-delay 21 --week 9 python3 scripts/cashflow13.py forecast.csv --json python3 scripts/cashflow13.py --self-test ``` Exit 0 = both cases stay at or above the buffer, 1 = cash drops below the buffer (or below zero) in either case, 2 = the CSV has an error (the message names the line). Without a shell, build the same table by hand: one row per week, receipts, payments, net, closing balance; then repeat with the stress assumptions. ### 3. Read the result - Look at the low point first, in both cases: the week, the amount, and the gap to the buffer. - Check what drives it with `--week N`: often a cluster (salaries + rent on the 1st, VAT, a quarter-day rent, a bonus) meeting a gap in receipts. - Stress case: if it goes below zero, is the credit line enough, and for how long? - Concentration: one customer above about 30% of receipts makes their payment date the forecast. - Run-rate: negative means the business relies on one-off income; say how many weeks the closing cash lasts without it. ### 4. Turn it into actions Use `references/cash-levers.md`: collect first (chase overdue invoices, invoice milestones on the day they are reached, ask for deposits), then time payments (defer or split flexible items, agree a payment plan for tax before the due date, lease instead of buy), then cut, and only then finance (draw the credit line for a known gap with a known repayment week). Re-run the forecast with each change so the owner sees the new low point. ### 5. Deliver and roll forward Fill `templates/cash-flow-brief.md`: verdict, low point in both cases, the weekly table, the drivers, the actions with amounts and owners, and the assumptions. Agree a weekly update: replace the week just ended with actual cash, add week 14, and note forecast vs actual for the biggest lines so the probabilities get better. ## Rules - Forecast cash, not profit: dates money moves, including VAT and payroll taxes, excluding depreciation and accruals. - Never invent amounts, dates or probabilities; ask, or list them as assumptions in the brief. - Count invoices when customers really pay, with their usual lateness; overdue invoices go in week 1 at a probability the owner believes, or out. - Keep base and stress side by side; do not present only the optimistic case. - Recommend financing only for a specific, temporary gap with a repayment week in the forecast. - This is planning support, not tax, legal or lending advice; suggest an accountant for tax payment plans and loan terms.