Startup Runway Calculator
(Cash Runway Tool)
Calculate exactly how many months of runway your startup has left from cash on hand and monthly burn — with an optional model for burn that grows as you hire.
Step 1 — Cash & Burn
Current balance across all business bank accounts
Cash spent minus cash earned each month — use our Burn Rate Calculator if you need to work this out
Calculated Results
Enter your cash on hand and monthly burn to calculate runway.
Runway Is the Single Most Important Startup Number
Runway answers the one question every founder eventually has to answer honestly: how many months until the business runs out of cash if nothing changes. It's a simple division, but the number it produces drives nearly every major decision — when to raise, when to cut costs, and how aggressively to spend on growth.
Why a Flat Burn Assumption Can Be Misleading
The simple formula assumes burn stays constant every month, but most growing startups increase spend as they hire — which means real runway is often shorter than the flat-rate number suggests. The optional growing-burn mode in this calculator simulates burn increasing by a set percentage each month rather than assuming it holds steady, giving a more conservative and often more realistic estimate for a team that's actively expanding.