Runway clock
Pull four live levers — price, CAC, churn, and your AI-agent ops spend — against a starting cash balance, and watch your exact zero-cash date move on every drag. Then read the sensitivity tornado: it ranks which single lever buys you the most months of survival. The usual surprise — the lever founders fixate on (price) is almost never the one with the most leverage. Runs entirely in your browser (0 uploads, works offline).
How to use it
- Set your starting cash and current numbers on the sliders — price per customer, CAC, monthly churn, new customers a month, and your fixed AI-ops stack spend.
- Watch the runway cliff (months of survival) and the burn curve recalculate live as you drag.
- Read the tornado — a 10% improvement on each lever, ranked by how many months it adds. The top bar is your highest-leverage move; the X-ray names it.
What this clears up (the fundamentals)
- Runway isn't one number — it's the output of four interacting levers. Cash ÷ this-month's-burn lies, because next month's burn depends on churn, growth, and acquisition cost.
- Sensitivity beats intuition — the lever that feels biggest (usually price) is rarely the one that moves the cliff most. A tornado chart ranks real leverage instead of gut feel.
- Churn compounds; price doesn't — a small churn cut keeps compounding into a larger base every month, while a price bump is a one-time step-change. That's why churn so often out-ranks price.
- The AI-ops line is now a real lever — a fixed agent/ops stack that scales with usage can quietly become the dominant cost; the model treats it as a first-class slider.
Where it's used
The Founders 'Metrics You'd Bet the Company On' lab, paired with the Cost & Latency Bench. A fast way to feel why "we'll just raise prices" is usually the wrong answer, and to find the lever your next quarter should actually target. It's a miatz build-lab concept playable; learn to build it yourself.
FAQ
How is the runway calculated?
Month by month: acquire new customers (paying CAC each), keep the rest after churn, bill them at your price for MRR, and subtract the fixed AI-ops spend — then draw the net burn from cash until it crosses zero. The cliff is the exact fractional month the balance hits zero.
Why does churn usually beat price on the tornado?
Because churn compounds. A 10% churn cut keeps a bigger customer base alive every future month, so its effect accumulates; a 10% price rise is a one-off lift on the current base. Over a runway of many months, the compounding lever wins.
What does "default-alive" mean?
If your plan never crosses zero cash within the 120-month horizon — revenue outgrows burn — you're "default-alive": the runway is effectively unbounded and the clock shows ∞.
Is anything uploaded?
No. Every number you enter and every recalculation happens in your browser — nothing is transmitted or stored. Turn off your Wi-Fi and it still works.
Limits
A teaching model with a simplified, single-cohort acquisition curve — it deliberately omits seasonality, expansion revenue, variable COGS, and financing events. Use it to build intuition about which lever matters, then take that lever to your real financial model.
Related
Part of the Demystify Playgrounds. Explore the rest from the Playgrounds home.
Bookmark this page (Ctrl+D, or ⌘D on Mac) — it works offline the next time you need it.