How do stacked SAFEs at different caps convert into a mess at my priced round?
The short answer
Every SAFE you sign at a different cap converts to equity at the priced round, and if you've raised on three or four caps over 18 months you can end up giving away far more than you think because the low-cap money converts into a large slice. Model the full cap table before you sign each new SAFE, not after, and treat every SAFE as real dilution today rather than a problem for future you. Founders routinely wake up at Series A owning 15 points less than they assumed because they never stacked the conversions.
Go deeper, your way
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Why we picked it
This is the worked walkthrough the question demands, not theory. It runs the exact scenario you fear: two SAFEs at different caps ($500K at $10M cap and $500K at $5M cap) converting at a $20M Series A, and shows the low-cap money buying twice the shares per dollar (1M shares vs 500K) so founders land ~3 points more diluted for the same money raised. It walks the conversion price math per SAFE, covers cap vs discount (investor takes whichever gives more shares), and hammers the point that the terms, not the dollars, are what dilute you. Free, no paywall, and specific enough to copy the numbers into your own model.
A low-cap SAFE converts to more shares per dollar, so $500K at a $5M cap costs you far more equity than $500K at a $10M cap even though it is the same cash
Each SAFE converts independently at its own cap or discount, whichever gives the investor more shares, so stacking compounds silently
The dilution is set the day you sign, not at the priced round, which is why you model the whole stack before signing the next one
Why we picked it
A practising senior partner spells out exactly why a raw US SAFE is dangerous for an Indian entity: it can be treated as a 'deposit' and trigger a FEMA or Companies Act violation, a landmine that only detonates when you reach Series A. It then names the compliant substitutes (iSAFE via CCPS or CCD, and the DPIIT convertible note) so you know what to actually ask your lawyer to paper.
Why we picked it
This is the modeling tool to actually stack your conversions before you sign, which is the whole opinionated answer. You enter each SAFE (pre-money or post-money, its cap, its discount) plus your fully diluted share count and a hypothetical priced-round valuation, and it converts every instrument at once and shows the founder and option-pool dilution that falls out. It handles the exact case founders get wrong: multiple SAFEs at different caps interacting, rather than a single clean instrument. Run it at several Series A valuations and you see the 15-point surprise before it happens instead of at the closing table. (Page was live but blocked our automated fetch, so verify the URL yourself.)
Model the full stack of SAFEs converting together, not one SAFE in isolation, since low caps quietly enlarge each other's slices
Pre-money and post-money SAFEs dilute differently: post-money guarantees the investor a fixed slice and pushes all the surprise onto founders and the pool
Stress-test at multiple Series A valuations, because a lower priced round makes low-cap SAFEs convert into an even bigger share
