Free dilution calculator

How this dilution calculator works

Two formulas, no magic. Priced round: post-money = pre-money + amount raised, and dilution = raise ÷ post-money. Post-money SAFE: the cap is the post-money, so dilution = amount ÷ cap. Your stake after is simply your stake before times one minus the dilution, because every existing holder shrinks by the same ratio.

The scenario table is the useful part. Valuation negotiations move in steps, and each step has a price in ownership: on a $2m raise, moving pre-money from $6m to $10m is the difference between giving up 25 percent and 16.7 percent. Seeing the whole spread before the meeting tells you exactly what a valuation point is worth - and when to stop fighting for one.

Two honest caveats. The option pool is not modelled - priced rounds usually carve 10 to 15 percent out of the pre-money before the money lands, which dilutes you further. And SAFEs only convert at the next priced round, so stacked SAFEs hit the cap table all at once, later. The full trade-off between the instruments lives in SAFE vs priced round, and the wider context in the fundraising process guide.

Frequently asked questions

How is dilution calculated?

For a priced round: post-money equals pre-money plus the amount raised, and the new investors' share - your dilution - is the raise divided by the post-money. Raise $2m at $8m pre-money and the post-money is $10m, so the round dilutes everyone by 20 percent. Existing holders all shrink pro rata: a founder at 100 percent drops to 80.

How does dilution work on a post-money SAFE?

On a post-money SAFE the cap is the post-money valuation, so the investor's ownership is fixed the moment you sign: amount divided by cap. $500k on a $5m post-money cap is 10 percent, full stop. That certainty is the point of the instrument - and it means every extra SAFE you stack comes straight out of the existing holders, which is mostly you.

What is a normal amount of dilution per round?

Rounds tend to land between 10 and 25 percent, with 15 to 20 percent the common middle at pre-seed and seed. Under 10 percent usually means you had real leverage. Over 25 percent in a single round is the market telling you the raise was too big for the valuation, and it compounds painfully across rounds.

Does this calculator model the option pool?

No, and the omission flatters you. Priced rounds usually require an option pool of 10 to 15 percent created or topped up before the money comes in - carved out of the pre-money, which means it dilutes existing holders on top of the round itself. Treat the numbers here as the floor of what the round costs.

When do SAFEs actually convert?

At the next priced round (or an exit). Until then the SAFE is a promise of future shares, not shares - so your legal cap table looks unchanged while your real ownership is already committed. Several stacked SAFEs converting at once is the classic founder surprise; model each one before you sign it, not after.