Tools · SAFE conversion calculator
Find out what your SAFEs actually convert into
Multiple SAFEs, caps, discounts, and a priced round. Pre-money and post-money SAFEs are modelled separately, because they price off different denominators. Runs entirely in your browser — we do not log your inputs.
Cap table before conversion
SAFEs outstanding
Ownership is locked in against the capitalisation after every SAFE converts, excluding the unissued pool.
The priced round
SAFEs convert inside the pre-money, so the new investors are not diluted by them. This model does not create a new option pool in the round — layer one on in the dilution calculator.
Round outcome
- Round price per share
- $2.2109
- Shares to SAFEs
- 1,045,937
- New investors
- 20.00%
- Existing holders
- 70.75%
Pre-money $20,000,000
9.25% of the company
2,261,484 shares
was 100.00%
Fully diluted shares go from 8,000,000 to 11,307,421 at a post-money valuation of $25,000,000. Existing holders give up −29.25 pp.
How each SAFE converts
| SAFE | Invested | Conversion price | Term used | Discount to round | Shares | % after |
|---|---|---|---|---|---|---|
| Pre-seed SAFE | $1,000,000 | $1.1055 | Cap | 50.00% | 904,594 | 8.00% |
| Angel SAFE (discount only) | $250,000 | $1.7688 | Discount | 20.00% | 141,343 | 1.25% |
Where a SAFE has both a cap and a discount, whichever produces more shares applies — they do not stack.
Ownership after the round
| Holder | Shares before | % before | Shares after | % after |
|---|---|---|---|---|
| Founder 1 | 4,500,000 | 56.25% | 4,500,000 | 39.80% |
| Founder 2 | 3,500,000 | 43.75% | 3,500,000 | 30.95% |
| Pre-seed SAFE | 0 | 0.00% | 904,594 | 8.00% |
| Angel SAFE (discount only) | 0 | 0.00% | 141,343 | 1.25% |
| New round investors | 0 | 0.00% | 2,261,484 | 20.00% |
Pre-money versus post-money SAFE
The same instruments, the same caps, the same round. The only change is which form was signed.
| Outcome | Pre-money SAFE | Post-money SAFE | Difference |
|---|---|---|---|
| Existing holders keep | 71.59% | 70.75% | −0.84 pp |
| SAFE holders get | 8.41% | 9.25% | +0.84 pp |
| Shares issued to SAFEs | 939,683 | 1,045,937 | — |
| Round price per share | $2.2372 | $2.2109 | — |
The difference is paid entirely by the existing holders. New round investors land on the same 20.0% either way, because their percentage is set by their money against the post-money valuation.
How this is calculated
- Post-money SAFE: the cap prices against the post-conversion count
price = cap ÷ (issued shares + granted options + all converting SAFEs)The unissued option pool is excluded, which is why a post-money SAFE holder’s percentage is locked in. - Pre-money SAFE: the cap prices against the pre-round count
price = cap ÷ (issued shares + granted options + unissued pool)Other converting SAFEs are excluded from the denominator, so each SAFE is priced as if it were the only one — and they dilute each other. - A discount prices off the round
price = round price × (1 − discount)With both a cap and a discount, whichever gives more shares applies. We also never price a SAFE above the round price. - The round prices off everything that already exists
round price = pre-money ÷ (existing fully diluted shares + all SAFE shares)SAFEs convert inside the pre-money, so their conversion dilutes the founders rather than the incoming investors. - Solve the circle
iterate until the SAFE share count stops moving (typically under ten passes)Post-money caps and discounts each depend on a total that depends on them, so the answer is a fixed point rather than a single formula.
Model boundaries, stated plainly: no new option pool is created in the round, interest and maturity on convertible notes are not modelled, and pro-rata or MFN side letters are ignored. Read your actual instrument — terms vary, and this is not legal advice.
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What this calculator does
A SAFE is a promise of future stock, not stock. Nothing happens to your cap table when you sign one — the reckoning comes at the next priced round, when every outstanding SAFE converts at once and the new investors buy in on top. This tool runs that moment: it prices each SAFE, issues the shares, prices the round, and shows you the cap table on the other side.
Each SAFE converts at the better of its valuation cap and its discount, if it has both. The cap sets a maximum valuation at which the money converts; the discount takes a fixed percentage off whatever the round price turns out to be. They do not stack — you get one or the other, whichever produces more shares.
The one thing people get wrong: pre-money versus post-money
Y Combinator replaced its 2013 pre-money SAFE with a post-money SAFE in 2018, and the two forms price off different denominators. The change looks cosmetic and is not.
Under a post-money SAFE, the cap divides by the capitalisation measured after every converting security has converted and excluding the unissued option pool. A $1m cheque on a $10m post-money cap is 10% of the company immediately before the new money — a fixed, knowable number the investor can rely on. Raise another SAFE afterwards and it does not touch their 10%; the founders absorb it.
Under a pre-money SAFE, the cap divides by the pre-round capitalisation, which includes the unissued option pool and excludes the other converting SAFEs. The same $1m on the same $10m cap buys fewer shares, and the more SAFEs you have outstanding, the further below the headline percentage each one lands. SAFEs dilute each other. That ambiguity is exactly why the form was replaced.
The practical consequence: stacking pre-money SAFEs quietly costs the investors, while stacking post-money SAFEs quietly costs the founders — and founders regularly discover at the priced round that they have sold far more of the company than they thought. Toggle the SAFE type above and watch the founder line move.
How to read the output
The conversion price column is the number that matters. Compare it against the round price per share: the gap is what the SAFE bought. The “term used” column tells you which clause did the work. If it says round price, the round priced below the cap and the SAFE holder got nothing for their cap — which happens, and which is worth knowing before the conversation.
SAFEs convert inside the pre-money, so the new investors are not diluted by them. That is why the incoming round lands on the same percentage whichever SAFE form you used, and why every point of difference between the two forms is paid by existing holders. This model does not create a new option pool in the round — most term sheets do, and that dilutes founders further, so layer one on in the dilution calculator after conversion. For the full explanation, read the SAFE guide. Read your own instrument before relying on any of this; nothing here is legal, tax, or investment advice.