Dilution Stack Calculator

It models the cap-table outcome when you raise multiple post-money SAFEs and then a priced Series A with an option pool refresh. Each SAFE converts at its own post-money cap, the Series A investor takes their priced percentage, the option pool is sized to the target post-round, and the residual is your founder ownership at close.

Most early-stage companies raise 2-3 SAFEs before a priced round; 3 slots covers the realistic range. If you have more, sum smaller SAFEs that share a cap into a single row (the math is identical), or open the calculator multiple times to compare scenarios. A future v2 may extend to N SAFEs.

v1 assumes each SAFE converts at its post-money cap (the cap-binding case). It does not model discount conversion. For cap-vs-discount math on a single SAFE, use the dedicated /tools/safe-calculator, it shows when the cap binds, when the discount binds, and the resulting effective valuation.

v1 sets the option pool as a target percentage of the post-round cap table and dilutes everyone proportionally, founders, SAFE holders, and Series A investors. The YC standard 'option pool comes out of pre-money' is an approximation that requires an iterative SAFE-and-pool waterfall; v1 simplifies for legibility. The difference is meaningful at large pool refreshes (>15%) and should be confirmed with your lawyer.

When SAFE ownership + Series A percentage + option pool sum to more than 100% of the post-round cap table, the founders' residual is negative, mathematically impossible in a real cap table. This usually means the SAFE caps are too low relative to the Series A pre-money, the SAFE amounts are too large for the caps, or the option pool target is too aggressive. The calculator flags this with a red band so you can adjust inputs.

Yes, every SAFE row + the entire Series A is encoded in the URL. The 'Copy share link' button copies the current URL to your clipboard. Send it to your co-founder, board, or lawyer and they open the calculator with the same numbers ready to inspect.