What is runway?
Runway is the number of months your startup can keep operating before it runs out of cash, assuming nothing else changes. It is a simple division — cash divided by net monthly burn — but it is arguably the single most important number a founder tracks. Runway determines how aggressively you can hire, how much you can invest in growth experiments, and most critically when you need to start your next fundraise.
Veteran founders speak about runway in two ways. The first is the literal number of months left at the current burn. The second is "runway to milestone" — how many months you have to hit the metric that unlocks your next round. The two can be very different. A team with 14 months of cash but a 12-month roadmap to product-market fit has effectively zero buffer. Treat runway as a planning tool, not just a survival metric.
Why does it matter so much? Because fundraising takes time. Even a fast Indian seed round usually consumes 3–4 months from first investor meeting to money in the bank. Series A often takes 4–6 months. If you wait until you have 4 months of cash to start raising, you will be negotiating from desperation — and investors can smell it. Strong runway gives you optionality, leverage and the ability to walk away from bad terms.
How is runway calculated?
The standard formula is straightforward: Runway (in months) = Cash on hand ÷ Monthly net burn. Cash on hand should include money in your operating accounts and short-term deposits, but exclude funds earmarked for taxes you owe. Net burn is monthly expenses minus monthly revenue, ideally averaged over the last 3 months to avoid spikes. If you expect burn to grow (because you're hiring or scaling marketing), build a forward-looking model rather than relying on a static number.
Healthy runway by stage
Most experienced investors recommend keeping at least 18 months of runway after closing a round, with 24 months being ideal. Pre-seed companies should aim for 18–24 months because the path to seed is unpredictable. Seed-funded startups should target 18–24 months to give them room to find product-market fit. Series A companies often plan for 24+ months because the cost of a stalled growth chart is so high. If you drop below 12 months, you are in fundraising mode whether you like it or not.
When to start fundraising
A useful heuristic: start the next raise when you have 9 months of runwayleft, expect 3 months of meetings and diligence, and want to close with 6 months still in the bank. If your business is more complex (deep tech, regulated, hardware), add 3 months to every step. If you're raising from international investors or larger funds, expect longer cycles. The goal is never to negotiate from a position of weakness — that almost always costs you valuation, terms, or both.
Tips for founders
- Recompute runway monthly with closed-month numbers, not budgets.
- Always model two scenarios: base case and a 20% revenue miss.
- Keep at least 6 months of runway as an emergency cushion at all times.
- Tie major hires to fundraising checkpoints, not vibes.
- If runway dips below 9 months, treat it as a P0 board-level conversation.
- Plan for a fundraise to take twice as long as you hope — closing early is a gift, not the default.