Startup Runway Calculator
How long will my cash last, and am I growing efficiently?
Also known as: SaaS burn multiple, runway & Rule of 40 calculator
This month
Default alive
- Burn multiple
- 1.7x
- Runway at today's burn
- 20 months
- Rule of 40
- 20
- Net burn a month
- ₹15,00,000
Good (1.5–2x)
Below 40.
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How it works
How does the Startup Runway Calculator work?
Burn multiple = net burn ÷ net new ARR in the same period (lower is better). The Rule of 40 adds growth rate and profit margin. Default alive asks whether revenue overtakes expenses before the cash runs out.
- Net burn = monthly expenses − monthly revenue; runway = cash ÷ net burn.
- Bands (David Sacks): under 1x amazing, 1–1.5x great, 1.5–2x good, 2–3x suspect, over 3x bad.
- Default alive (Paul Graham): expenses held flat, revenue growing at your current monthly rate; checked month by month for up to 20 years.
- Rule of 40 = YoY revenue growth % + profit margin % (EBITDA or free cash flow).
Worked example
₹3 crore cash, ₹25 lakh revenue and ₹40 lakh expenses a month: net burn ₹15 lakh, runway 20 months. Adding ₹9 lakh net new ARR a month gives a burn multiple of 1.7× ("good"). Growing revenue 6% a month with flat expenses reaches profit in month 9: default alive.
Limits
Default alive assumes expenses stay flat and growth holds; both rarely do. Use the same period for burn and net new ARR.
Sources
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This free calculation runs locally and is a planning aid, not financial, tax or legal advice. Nothing you type leaves this page unless you choose to save it.