Post-money SAFE

A post-money SAFE is a promise to issue shares later, priced today by a single number: the post-money valuation cap. The investor's ownership fraction is simply investment ÷ cap. That fraction is locked in the moment the SAFE is signed — it does not move with the company's performance, the size of the eventual priced round, or (mostly) how many other post-money SAFEs you stack on top of it.

Why 'post-money' matters

Before 2018, SAFEs used a pre-money cap, and a founder raising several of them in sequence couldn't know their own ownership until every SAFE was accounted for — each new SAFE diluted the cap-implied ownership of the ones before it in a way that was hard to predict. The post-money SAFE fixed this: because the cap is expressed as a fraction of the post-money company, a $200,000 SAFE at a $4,000,000 post-money cap always means the investor owns 5% of the company as it stood immediately after all post-money SAFEs from that round closed — full stop.

Stacking SAFEs

If you raise two post-money SAFEs with different caps, each investor's ownership is still just their own investment ÷ their own cap. What changes is the founders' residual: with two SAFEs claiming 5% and 8% respectively, the founders are left holding 87% of the pre-round cap table, not 100% minus one SAFE's slice. Foundily's SAFE calculator and cap table builder both handle this mutual-dilution math for you — you never need to do it by hand.

What happens at the priced round

The SAFE converts into common-equivalent (usually 'Series Seed Preferred') shares at the priced round, using the share count implied by its cap. From that point on, the SAFE holder is diluted exactly like a founder — proportionally, by the new investor's shares and any option-pool top-up. See the dilution glossary entry and the /calculators/dilution tool to trace this through a full round.