SAFE Conversion Calculator: Post-Money and Pre-Money SAFEs
SAFE conversion calculator built on Y Combinator's definitions: caps, discounts, MFN and the pool top-up, for post- and pre-money SAFEs in one round.
- Service
The calculator
01 The table before the SAFEs
02 The instruments waiting to convert
A post-money SAFE sells the holder a fixed share of the company before the round. A pre-money SAFE or note converts at a price set by its cap, and pre-money instruments dilute each other.
03 The priced round they convert into
- Common holds
- n/a
- Post-money
- n/a
- Total in
- n/a
The table once everything converts
| Holder | Shares | Ownership | Money in |
|---|
Instrument by instrument
| Instrument | Amount | Cap price | Discount price | Converts at | Shares | Ownership | Wins on |
|---|
How this was worked out
What this model assumes
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<p>SAFE conversion calculator by <a href="https://www.spectup.com/calculator/safe-conversion">spectup</a></p>Keep the line under the frame: it is a plain link to this page, where the method is written out.
How to use spectup's SAFE Conversion Calculator
- 01Set the table before the SAFEs
Enter the shares and granted options in issue and the unallocated pool. The figures and the four instruments filled in are an example to overwrite.
- 02List every SAFE and note
Give each instrument its amount, cap and discount, mark it post-money or pre-money, and switch on MFN where the document has it. Leave the cap blank for an uncapped SAFE.
- 03Set the priced round
Enter the pre-money, the new money and the pool the lead wants after closing. The table, the instrument ledger and the before-and-after chart update as you type.
The method behind the SAFE conversion calculator
At the next priced round a SAFE turns into shares, at whichever price gives its holder more shares: the price its valuation cap sets, the round price less its discount, or the round price itself. This SAFE conversion calculator works that out for every instrument in the stack and shows the cap table once all of them have converted.
For founders and CFOs with a Series A in sight, the SAFEs and notes land in the same table as the new investor. That priced round is where spectup's capital raising work starts: spectup runs it as a startup fundraising consultant, from the plan to the close.
How does a SAFE convert in a priced round?
The cap price is the valuation cap divided by the company's share count. The discount price is the round's price per share less the discount. The round price itself applies only to a SAFE with no discount, when the round prices below its cap.
Which one wins depends on the round. Take a post-money SAFE of $500,000 with a $20M cap and a 20% discount, converting into a $3M round at $12M pre-money on 10,000,000 shares.
The cap price comes out at $1.8958 a share, because a post-money cap is divided by the shares after conversion, the SAFE's own included; the round price is $1.1375. So the cap does nothing. The discount takes 20% off the round price: the SAFE converts at $0.91 and receives 549,451 shares, 4.17% of the company after the round, which is what the SAFE conversion calculator above returns.
The share count the cap is divided by is where post-money and pre-money SAFEs part company. Y Combinator, which wrote both forms, sets out what each one counts in the user guide on its SAFE documents page:
Counted in the capitalization | Pre-money SAFE | Post-money SAFE |
|---|---|---|
Shares and options in issue | Yes | Yes |
Unallocated option pool | Yes | Yes |
Pool increase for the round | Yes | No |
SAFEs and convertible notes | No | Yes |
That table decides who bears the dilution. A pre-money SAFE's price ignores the other SAFEs, so they all dilute each other; a post-money SAFE counts every converting instrument, so its percentage holds whatever else is raised on SAFEs.
What does a post-money SAFE sell?
A fixed share of the company as it stands after all the SAFEs and before the round: the amount divided by the cap. Y Combinator's quick-start example puts $1M at a $6.7M post-money cap at about 15%.
The priced round then dilutes that share like any other, because the round's post-money valuation includes new shares the SAFE never counted. In Y Combinator's own worked example, a $200,000 SAFE at a $4M cap is 5% once the SAFEs convert.
After a $5M Series A at $15M pre-money, with the unallocated pool topped up from 1% to 10%, the same SAFE holds 3.28%. Enter those figures in the calculator above, 9,900,000 shares and options in issue, and it returns the same.
| Step | Change | Running total |
|---|---|---|
| After the SAFEs convert | 5.00% | |
| The $5M of Series A money | −1.25% | 3.75% |
| The pool top-up | −0.47% | 3.28% |
| After the Series A | 3.28% |
Pre-money or post-money SAFE: what the difference costs
Take 8,000,000 shares in issue, two SAFEs of $1M each at an $8M cap, and a $2M round at $18M pre-money. As pre-money SAFEs, each ends the round with 9% and common with 72%; as post-money SAFEs, each with 11.25% and common with 67.5%.
| Scenario | Pre-money SAFEs | Post-money SAFEs | Gap |
|---|---|---|---|
| Common, two SAFEs | 72% | 67.5% | 4.5 pts |
| Each SAFE, two SAFEs | 9% | 11.25% | 2.25 pts |
The post-money form costs common 4.5 points here. Its cap is divided by a count that already includes the SAFE shares, its own and the other one's, so each holder buys a fixed share and common carries the rest. With a single SAFE the gap is smaller, 78.75% against 80%, and it grows with every SAFE added.
Inside this SAFE conversion calculator, step by step
- The table before anything converts: shares and granted options, plus the unallocated pool.
- The round: the new investor buys new money divided by post-money, and the pool is topped up to its target inside the pre-money.
- The circle, solved: the round price needs the share count, the SAFEs need the price, and the pool target needs the total. The calculator repeats the solve until the figures stop moving.
- Each instrument converts at its lowest price, on the capitalization its type counts.
- Most favoured nation: an MFN holder takes the terms of a later instrument of the same type, as a package, when they give it more shares.
| Step | Leads to |
|---|---|
| Round price (pre-money / share count) | SAFEs convert |
| SAFEs convert (each at its lowest price) | Pool top-up |
| Pool top-up (to its target) | New share count |
| New share count (repeat until nothing moves) | Round price [moved]; The table after the round [settled] |
| The table after the round | end |
For the rounds after this one, the cap table calculator takes the converted table forward.
What does the SAFE conversion calculator leave out?
Notes behave like pre-money SAFEs here, without their interest. Interest is added to the principal before a note converts, so enter principal plus accrued interest; convertible notes have their own page.
Pro rata side letters and share rounding are left out too, and the calculator can only read the terms you type: where your documents say something different, they win.
The model also assumes a priced round happens. A SAFE has no maturity date and waits for a priced round, a sale or a listing, and the SEC's investor bulletin on SAFEs notes that a company that never again needs to raise capital, and is never sold, may never trigger it.
How spectup prices the SAFEs into the round
The SAFEs stop being a side matter the day a lead investor names a pre-money and a pool, because both move every conversion. On a Series A to pre-IPO mandate, spectup's round plan covers the round size, the instrument and the dilution, so the outstanding SAFEs and notes go into it as conversions.
The work is paid by a monthly fee during the round and a success fee once it closes and the money is in.
Questions readers ask about this calculator
What people search for alongside this calculator, answered.
01What happens if a SAFE never converts?
It stays outstanding: a SAFE has no maturity date and no repayment schedule. If the company is sold first, the holder receives its money back or the value of the shares its cap would have bought, whichever is larger; in a wind-down it ranks behind creditors and alongside preferred holders.
02What does it mean for a SAFE to convert?
The company issues the holder shares in the priced round, usually a separate series of preferred stock priced at the SAFE's own conversion price, and the SAFE ends.
03Do you have to pay back a SAFE?
Not in the ordinary course. A SAFE is not debt: it has no interest and no maturity date. If the company is sold or wound down before a priced round, the holder is paid out of the proceeds.
04How does a SAFE convert to equity?
The holder takes the lowest of three prices: the cap divided by the company's share count, the round price less the discount, or the round price itself. The amount divided by that price is the number of shares. Which share count the cap is divided by depends on the form: a post-money SAFE counts every converting instrument and leaves out the pool increase for the round, a pre-money SAFE does the reverse. The SAFEs then sit in the table beside the new investor.
05Does a post-money SAFE dilute founders more than a pre-money SAFE?
Usually, at the same cap figure. One $1M SAFE at an $8M cap converting into a $2M round at $18M pre-money, with no pool, leaves common at 78.75% as a post-money SAFE and 80% as a pre-money one; with two such SAFEs it is 67.5% against 72%. A large pool top-up can reverse it: a pre-money SAFE's share count includes the top-up, so the SAFE escapes that dilution and common carries it. With a 15% pool target, the single SAFE leaves common at 65.63% as post-money against 65% as pre-money.
06Should I hire a startup fundraising consultant before my SAFEs convert?
If the SAFEs convert into a Series A or later, before the lead names a pre-money, because every conversion moves with it. spectup is a startup fundraising consultant for those rounds and charges a monthly fee during the round and a success fee once the money is in.
The other three calculators
Each one shows its own arithmetic, from a round to a sale.
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