Dilution slider
Drag round size, pre-money valuation, and option-pool top-up across up to four funding rounds and watch a live ownership donut — plus a founder-ownership-over-time line — recompute on every tick. Then read the moat overlay: exactly how much of your shrink came from investor terms versus the option-pool top-up nobody argued about. Runs entirely in your browser (0 uploads, works offline).
How to use it
- Set each round's raise, pre-money valuation, and option-pool top-up % on the sliders (add or remove rounds up to four).
- Watch the donut (final cap table) and the founder line recompute live — round by round, who dilutes whom and by how much.
- Read the "dilution you didn't negotiate" reveal — the split between investor-term dilution and pool-top-up dilution, in ownership points.
What this clears up (the fundamentals)
- Dilution is two negotiations, not one — the raise (investment ÷ post-money) is the one everyone watches; the option-pool refresh is the quiet one that also comes straight out of your slice.
- Pool top-ups are usually pre-money — they're carved out before the new money lands, so they dilute founders alone rather than everyone pro-rata. That's why the same headline valuation can leave you with very different ownership.
- Dilution compounds — a slice given up in the seed round is itself diluted again at Series A. Early points cost more than late points.
- Post-money math — investor ownership is investment ÷ (pre-money + investment). Once you see it as a fraction of post, term sheets stop being mysterious.
Where it's used
The Founders L1 onboarding lab, paired with the Term-Sheet Table — a free lightning lesson on why "we only sold 20%" and "I only kept 56%" are both true. It's a miatz build-lab concept playable; learn to build it yourself.
FAQ
How is investor ownership calculated?
Per round, the investor's stake is investment ÷ post-money, where post-money = pre-money + investment. Everyone who already held shares keeps their share count and simply owns a smaller fraction of the enlarged total.
Why does the option pool dilute only founders?
Because refreshes are typically negotiated pre-money: the new pool is created before the round closes, so it comes out of the existing (mostly founder) cap table rather than being shared with the incoming investor. The overlay isolates exactly how many points that costs you.
Why is my dilution more than the percentages I sold?
Because it compounds. Selling 20% at seed and 20% at Series A doesn't leave you with 60% — the seed dilution is re-diluted by the A round. The founder line shows the compounding directly.
Is anything uploaded?
No. Every slider value and every recomputation happens in your browser — nothing is transmitted or stored. Turn off your Wi-Fi and it still works.
Limits
A teaching model that uses a clean post-money framework and treats each pool refresh as a straight percentage of post — it deliberately omits SAFEs/notes converting, pro-rata rights, anti-dilution ratchets, and per-share price mechanics. Use it to build intuition, then model your actual term sheet in a full cap-table tool.
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.