Cash-Runway Planner

What this tool does

CM8-10 projects a monthly cash position for a small business, startup or project over a 24–36 month horizon. You describe the plan in three lists — recurring revenue streams, recurring expenses, and one-off events — and the tool computes revenue, expenses, net cash flow and the ending cash balance for every month, in Base / Best / Worst scenarios side by side.

Everything runs inside this single HTML file. No installation, no account, no network requests — your financial assumptions never leave your computer.

Burn rate vs. runway, in plain words

Burn rate is how much cash the business loses per month:

If you spend 40,000 a month and bring in 13,000, your net burn is 27,000/month. If revenue exceeds expenses, net burn is negative — you are cash-generating, not burning.

Runway is how long the cash lasts at that pace:

That simple division assumes burn stays constant. It rarely does — revenue grows, salaries rise, taxes fall due in specific months. That is why this tool computes runway the honest way: it walks the projection month by month and reports the first month in which the ending balance drops below zero — the cash-out month. If the balance never goes negative within the horizon, the runway is shown as “> horizon”.

How the projection works

Recurring items and growth

Each revenue stream and expense has a monthly amount, an optional growth rate (% per month) and a start month (expenses also take an optional end month). Growth compounds from the item's own start:

Compounding is powerful: 5%/month is ≈ 80% per year; 10%/month more than triples in a year. If you only know an annual growth figure, divide by 12 for a close-enough monthly rate at small percentages, or use (1+annual)^(1/12) − 1 to be exact.

One-off events

One-offs land in a single month with the sign you give them: negative for cash out (tax payment, equipment purchase, security deposit), positive for cash in (funding round, grant, asset sale, tax refund). Scenario adjusters never scale one-offs.

Each month, in order

1. Sum all active revenue streams (grown, then scenario-adjusted).
2. Sum all active expenses (grown, then scenario-adjusted).
3. Add any one-off events for that calendar month.
4. Net = revenue − expenses + one-offs; ending cash = previous cash + net.

Scenarios: Base / Best / Worst

The Base scenario is exactly what you typed. Best and Worst apply flat percentage adjustments to every recurring revenue and expense — e.g. Worst at revenue −25% / expenses +10% answers “what if sales disappoint and costs creep?” in one click. Sensible defaults are provided; tune them to your risk appetite. The comparison table shows all three runways side by side — the gap between Base and Worst runway is your margin for error. Plan hiring and spending against Worst, not Base.

Reading the chart

• Each line is the projected end-of-month cash balance for one scenario — Base solid blue, Best dashed green, Worst dotted amber. The active scenario is drawn bold.
• The dashed dark line is zero. Where a cash line crosses it, that scenario runs out of money.
• The red marker names the cash-out month for the active scenario.
• Hover (or touch) the chart to read exact balances for all three scenarios in any month. The same numbers, to the cent, are in the Projection tab.

Good practice for cash planning

• This is a cash model, not a P&L. Enter amounts in the month the money actually moves. If customers pay 60 days late, shift that revenue two months later. Accrual profit and cash in the bank can differ wildly.
• Do not forget the lumpy stuff: annual insurance premiums, tax instalments, software renewals, bonuses, 13th-month salaries — enter them as one-off events.
• Payroll costs more than salaries. Add employer taxes and benefits — commonly 1.15–1.4× base salary depending on jurisdiction.
• Treat unsigned funding as a scenario, not a fact. Model the plan without the round first; add the round as a positive one-off only when it is truly committed.
• Revisit monthly. Update starting cash and the as-of month against your real bank balance, and compare last month's projection to what actually happened.
• Horizon: 24 months is standard for planning; 36 shows the longer arc but the far months are soft. For week-level precision near a crunch, a 13-week cash flow is the companion discipline — this tool works at month grain.

Saving your work

• Autosave: the whole plan is kept in this browser's local storage (when the browser allows it) and restored next time you open the file. The indicator in the top bar shows the last autosave time.
• Save: writes the plan to this browser immediately and confirms with “Saved ✓” and the time — useful before closing the tab. It stays on this machine and in this browser; it is not a file.
• Export .json: a portable file with every assumption — archive it, version it, or move it to another machine and use Import .json there.
• Export CSV: the full monthly projection for the active scenario, plus ending cash for all three scenarios — ready for a spreadsheet or a board pack.
• Print Report: builds a clean report — title block, executive tiles (cash on hand, net burn, runway, cash-out date), all three figures, the scenario comparison, the monthly table and your closing notes — then opens the print dialog (“Save as PDF” works too). Fill in Report settings on the Projection tab first; those fields are saved with the plan.
• Reset needs two presses: the first arms the button (“Confirm reset?”), the second — within five seconds — erases the plan and the saved browser data and returns the tool to a clean start. Click away or press Escape to cancel.