What is runway and how much should a round buy?

Runway is the months a company can operate before cash runs out: cash balance divided by net burn. Rounds are conventionally sized to buy 18–24 months — enough to hit the next milestone and raise again before the final months of desperation pricing.

Fundraises take 3–6 months in normal markets; starting with a year of runway is starting late. Extending runway by cutting burn is always compared against the dilution cost of raising more.