Startup Runway & Valuation

Runway, burn, and why the naive math misleads

The textbook formula — runway = cash ÷ monthly net burn — assumes your burn stays flat. It almost never does. Salaries rise, headcount grows, server bills scale, and hopefully revenue climbs too. This calculator models a dynamic runway: expenses increase at your chosen rate while revenue grows at its own rate, and the tool solves for the month your cash actually crosses zero. The difference is not academic — a startup with $100k cash and $15k burn has "6.7 months" by naive math, but if burn grows 10% annually while revenue grows from $2k at 5% monthly, the real runway shifts meaningfully.

Net burn is what matters: total spending minus revenue. Gross burn tells you your cost base; net burn tells you your survival clock. Investors ask for both, but the clock runs on net.

How much runway should you actually target?

The venture convention is 18–24 months per round: 12–15 months to hit the milestones that justify the next raise, plus roughly 6 months to run the fundraising process itself. Raising for less puts you back on the road almost immediately; raising for much more usually means excessive dilution at your weakest valuation. The funding-need tab encodes exactly this logic — pick your target runway, and it sums the projected burn over those months plus your buffer.

In tighter funding climates, founders stretch to 24–30 months by cutting burn rather than raising more — every month of runway bought by discipline costs no equity.

Early-stage valuation without the mystique

Before meaningful profits, discounted-cash-flow valuation is fiction, so early-stage pricing leans on two anchors: revenue multiples (annualized revenue times a sector multiple — SaaS commonly 5–10x ARR, marketplaces and services lower) and stage norms (what seed or pre-seed rounds in your ecosystem typically price at, regardless of revenue). The estimator blends both, adjusted for growth rate, because a company growing 100% a year deserves a higher multiple than one growing 20%.

Remember the dilution arithmetic: ownership sold = amount raised ÷ post-money valuation. Raising $500k at $2M pre-money is $2.5M post-money — 20% of the company. Optimizing the amount you raise usually beats optimizing the headline valuation.

Mistakes that quietly shorten runways

• Counting committed-but-unwired money as cash. Runway runs on the bank balance, not the term sheet.
• Modeling revenue growth without its costs. Sales hires and marketing spend usually precede the revenue they generate — grow burn and revenue together.
• Ignoring annual lumps. Insurance renewals, audit fees, and annual software contracts can eat a month of runway in one invoice; put them in one-time expenses.
• Updating quarterly. Close the books monthly and re-run the model — burn drift compounds silently.
• Fundraising at 4 months of runway. Processes take 3–6 months; starting late converts a negotiation into a distress sale.

Related decisions worth quantifying

Runway pressure makes every cost decision sharper. Our break-even calculator shows whether your current trajectory ever reaches profitability without another raise; hire-vs-outsource compares the fully loaded cost of the next role against contracting it; and founder time value tells you which of your own tasks are cheapest to delegate — often the fastest burn reduction available.