It’s not a lack of money that kills a startup: it’s not knowing your rate of cash consumption. Managing your cash flow and tracking your burn rate isn’t an accounting exercise reserved for large companies — it’s the skill that determines how much time a founder has left to correct course before running out of options.
Cash, burn rate, runway: three numbers to know by heart
Before building anything, clarify the vocabulary. These three notions are often confused, even though they answer different questions.
| Term | What it measures | How to estimate it simply |
|---|---|---|
| Available cash | The money actually in the account, today | Current bank balance, excluding unpaid invoices |
| Burn rate (monthly) | The net rate of cash consumption | This month’s cash out minus cash actually received this month |
| Runway | Time left before hitting zero, at the current rate | Available cash divided by the monthly burn rate |
A runway of 8 months doesn’t mean you have 8 months to think it over: it’s the time you have left to act, not to wait for things to sort themselves out.
The “profitable on paper” trap
A startup can show growing revenue and still run out of cash the following month. The most common cause: an invoice is not a payment received. Between issuing an invoice and actually receiving the money, several weeks — sometimes several months — can pass, especially with large accounts or public institutions, whose payment circuits rarely match the terms stated in the contract.
This gap has a name: working capital requirement. The faster a business grows, the larger this gap becomes. A startup signing more contracts can, paradoxically, see its cash position tighten if it doesn’t finance this gap between immediate expenses (salaries, vendors, materials) and the client’s delayed payment.
Limits of this exercise. A cash-flow sheet built alone, with optimistic assumptions about payment delays, does not replace the advice of a chartered accountant — especially before a fundraising round or a change of legal status. And no tracking method turns a flawed business model into a good one: if the margin on each sale doesn’t cover fixed costs, that’s no longer a cash-flow problem, it’s a fundamental one, and should be treated as such.
Building a cash-flow sheet in three steps
You don’t need specialized software to start. A spreadsheet is enough, as long as you keep it up to date.
- List expected cash inflows, with a probability. For each expected inflow (a signed sale, a grant, a personal contribution), note the realistic collection date — not the invoice date — and an honest probability: 100% for a transfer already received, 50% for a client who “said yes” without a signed contract, not 100% out of optimism.
- List cash outflows, both fixed and variable. Salaries, rent, software subscriptions on one side; one-off purchases, vendors, travel on the other. Fixed costs are the ones that continue even without any activity: they set your floor burn rate, the one you pay even in a month with zero sales.
- Update it every week, not every quarter. A sheet frozen at the start of the month loses all usefulness the moment a payment slips by a few weeks. How often you update it matters more than how sophisticated the tool is.
This work connects to a documented failure cause covered in our article on why startups fail: poorly anticipated cash flow regularly ranks among the most cited causes, alongside a lack of paying customers and an incomplete team on a key skill.
Special case: grants, prizes and support programs
A grant, a competition prize or support from an incubation program doesn’t behave like a sale. Many of these mechanisms pay out funds after expenses are justified, or in installments tied to milestones reached — not all at once at the moment of selection. For the exact calendar and disbursement terms, always check the official page of the program in question rather than a general estimate: these details vary from one scheme to another and change over time.
The practical consequence is simple: as long as the funds aren’t in the account, they shouldn’t appear at 100% probability in your cash-flow sheet. A founder who needs to cover an expense before a disbursement has to plan for that advance elsewhere — their own cash, bridge financing, or a spread-out payment arrangement with a supplier — otherwise an administrative scheduling gap quietly turns into a real cash-flow problem.
Reading your runway to decide, not to worry
Runway is only useful if it triggers a decision. These are decision points, not universal certainties: adjust them to your sector and sales cycle.
| Runway left | What it means | Action to consider |
|---|---|---|
| More than 9 months | Comfortable room to maneuver | Invest in growth, document the hypotheses still to be tested |
| Between 4 and 9 months | Window still open, but closing | Start fundraising or raising funds now, not in the final month |
| Less than 4 months | Immediate risk zone | Cut fixed costs without delay; funding never closes as fast as hoped |
Why “less than 4 months” is a warning threshold. Between a first contact with an investor or a funder and the money actually landing in your account, several months often pass: discussions, due diligence, negotiating terms, signing. Waiting until you have 2 months of runway left to start looking for funding means negotiating under pressure, from a position of weakness rather than choice.
Monthly warning signs to watch
- The average delay between invoicing and payment is stretching month over month.
- A single client accounts for a growing share of collected revenue, creating dependency.
- Fixed costs are rising faster than recurring cash inflows.
- The number of follow-ups needed to get paid is increasing.
- Actual monthly burn consistently exceeds what was planned in the sheet.
None of these signs is, on its own, a reason to panic. Repeated over several months and combined with each other, they signal a cash crunch well before it becomes visible on the bank balance — and that lead time is exactly what still allows you to act.
Actionable checklist
- I know my current available cash balance, not a figure from a month ago.
- I have calculated my net monthly burn rate over the last three months, not just as a forecast.
- I have a calculated runway, expressed in months, not as a rough order of magnitude.
- My cash-flow sheet distinguishes certain inflows from probable ones.
- I update this sheet every week, not once a quarter.
- Grants or prizes not yet received are not counted as available cash.
- If my runway drops below 4 months, I have already identified which costs to cut first.
- I have checked with a chartered accountant that my tracking reflects my actual situation, not just my assumptions.
Conclusion
Managing your cash flow is neither an administrative detail nor a skill reserved for finance profiles. It’s the most honest indicator of a startup’s real state, often ahead of its growth numbers. A founder who knows their runway down to the month keeps the ability to decide; one who discovers it at the same time as a bank overdraft has already lost that room to maneuver.
Next step: calculate your current runway using the table above, then build this tracking habit into an EIC support program, where mentoring and regular milestones help keep this discipline going over time.
