The short answer: with a post-money SAFE, each SAFE holder owns roughly the amount invested divided by the post-money valuation cap, measured before the priced round. At the priced round, everyone, including the SAFE holders, is diluted again by the new money and by any increase to the option pool. The calculator below runs both steps on your numbers.
How to use the calculator
- Your cap table today. Enter founders and the employee option pool as percentages of the fully diluted company. Anything left over is treated as earlier shareholders, for example angels from a previous round.
- Your SAFEs. One line per SAFE or per group of SAFEs on the same terms: the amount, the post-money valuation cap and the discount, if there is one. Leave the cap empty for an uncapped SAFE.
- The priced round. The pre-money valuation the lead offers, the amount you raise, and the option pool the investors want to see after the round.
A worked example
These are the calculator's default numbers. Founders own 90% and the option pool is 10%. The company raises two SAFEs: $500K at a $5M post-money cap and $1M at an $8M post-money cap. A year later it raises a $3M seed round at a $12M pre-money valuation, and the lead asks for a 10% option pool after the round.
| Holder | Today | After the SAFEs | After the seed round |
|---|---|---|---|
| Founders | 90% | 69.8% | 52.9% |
| Option pool | 10% | 7.75% | 10% (incl. a 4.1% top-up) |
| SAFE 1 ($500K at $5M) | - | 10% | 7.59% |
| SAFE 2 ($1M at $8M) | - | 12.5% | 9.49% |
| Seed investors ($3M) | - | - | 20% |
Three things stand out. Each post-money SAFE owns exactly its amount divided by its cap, so the two SAFEs together take 22.5% before any priced money arrives. The seed investors get exactly $3M divided by the $15M post-money, which is 20%. And because the larger option pool is created before the new money comes in, the top-up is paid for by the founders and the SAFE holders. The founders end at 52.9%, a 41% reduction from the 90% they started with.
What drives the result
- Post-money SAFEs stack.Y Combinator describes post-money SAFE ownership as measured after all the SAFE money is accounted for. Each additional SAFE therefore dilutes the founders and earlier holders, while every earlier SAFE holder keeps the percentage their cap implies until the priced round.
- The cap versus the round price.At the priced round, a SAFE converts at whichever price gives its holder more shares: the cap price or the round price less any discount. If the round is priced below the cap, the cap stops mattering and the SAFE converts at the round price or the discount.
- The option pool shuffle.When the lead asks for a larger pool inside the pre-money valuation, the new options come out of the existing holders' share and the new investor keeps its full percentage. Venture Hacks named this the option pool shuffle back in 2007. Sizing the pool to a real 12 to 18 month hiring plan is the most direct way to limit it.
- Valuation is only one lever.The amount you raise, the size of the pool and the number of SAFEs you stack before the round often move the founders' final ownership as much as the headline valuation.
What the calculator assumes
- Post-money SAFEson Y Combinator-style terms, converting at the next priced round. Pre-money SAFEs and convertible notes with interest convert differently.
- One priced round,with the option pool top-up in the pre-money and SAFE shares counted in the pre-money.
- No side terms.Pro-rata rights, MFN clauses, warrants and liquidation preferences are not modelled. They do not change the percentages at conversion, but they matter later.
- An estimate.Real documents round share counts and define capitalization in detail. Use the result to plan and negotiate, then confirm the numbers with your lawyer before you sign.
SAFEs are the default instrument at the Israeli pre-seed stage: in Fusion's 2025 survey, as reported by VC Cafe, 69% of angels invested only through SAFEs. Our guide to SAFEs in Israel covers the Israeli tax and legal points, and the seed round guide covers what investors expect at the priced round.