A stack of SAFEs and convertible notes converted into a priced round. Pre-money and post-money instruments are handled by their own rules, mixed stacks are solved simultaneously, and every input is encoded in the URL.
| Amount | Valuation cap | Discount % | Type | Rate | Years | MFN | |
|---|---|---|---|---|---|---|---|
| Enable JavaScript to edit the instrument stack. The formulas, the worked comparison, and the parameter reference below are static text and do not require it. | |||||||
The bars re-run the identical stack with every instrument treated as pre-money, then as post-money. The new investor's percentage is unchanged either way; the difference is taken from founders and existing holders.
Converting instruments and any newly created option pool sit inside the pre-money share count, so the new investor's percentage is fixed by its cheque and the post-money valuation and every additional converting share dilutes only the existing holders.
The cap is divided by a capitalisation that excludes the shares issuable on conversion of the instruments, so the share count is fixed before the round price is known. Several pre-money instruments converting into the same round dilute one another.
The cap is divided by the capitalisation after all instruments convert and before the new money, so the instrument fixes a percentage rather than a share count. Later instruments no longer dilute earlier ones; founders and existing holders absorb all of it.
A post-money instrument takes a fixed percentage of a base that includes all converting shares. A pre-money instrument takes a fixed share count from a base that excludes them. Put both in one round and each depends on the other, so the stack is solved simultaneously.
With one pre-money instrument issuing 400,000 shares against FD = 8,000,000 and one post-money instrument at w = 0.125: S = 8,400,000 / 0.875 = 9,600,000, so the post-money instrument takes 1,200,000 shares rather than the 1,142,857 it would have taken alone. It is diluted by nothing and expanded by everything. This calculator solves the stack numerically, so a discount, an MFN election, or accruing interest in the same stack is handled without a closed form.
An instrument carrying both converts at whichever produces the lower price. The switchover depends only on the cap and the discount, not on the share count, so it is known the day the instrument is signed.
The switchover is independent of the share count, because the count cancels out of both sides, so it can be computed the day the instrument is signed. The discount price itself is not. It is the discount applied to the actual round price p = PRE / S, and S includes the shares issuing on conversion and any new pool, so price and share count are solved together rather than in sequence. An illustration that divides the pre-money valuation by the pre-conversion count alone identifies the same binding term but quotes a higher discount price for the same instrument.
Accrued interest buys extra shares at the same conversion price, which is arithmetically identical to a discount on the price once the holding period is fixed. Interest and a stated discount stack multiplicatively, not additively.
An MFN instrument may elect the terms of a later qualifying instrument issued before conversion. Here the election is modelled as taking the lowest cap of any later capped instrument in the stack, the instrument's own form being unchanged.
A term sheet stating a pool percentage has not stated what the percentage is measured against. Both conventions are supported and they give different pool sizes, different prices, and a different cost to founders on identical headline terms.
A cap is a ceiling on price, not a floor on ownership. The standard documents convert a capped instrument at the cap price even where the round prices below it, so this calculator does not floor the conversion price at the round price. Where an instrument carries a discount as well, the discounted round price is compared and the lower of the two is used. Conversion price definitions vary between templates; read the specific document.
Reference values. One instrument of 1,000,000 at an 8,000,000 cap, no discount, on 8,000,000 pre-round fully diluted shares, converting into a 3,000,000 round at a 12,000,000 pre-money valuation and no new pool.
| Quantity | Pre-money SAFE | Post-money SAFE |
|---|---|---|
| Existing fully diluted shares | 8,000,000 | 8,000,000 |
| Capitalisation the cap divides by | 8,000,000, excluding SAFE shares | 9,142,857, including SAFE shares |
| SAFE conversion price CP | 1.0000 | 0.8750 |
| SAFE shares issued | 1,000,000 | 1,142,857 |
| Pre-money share count for pricing the round | 9,000,000 | 9,142,857 |
| Round price per share | 1.3333 | 1.3125 |
| New shares for 3,000,000 | 2,250,000 | 2,285,714 |
| Total shares after close | 11,250,000 | 11,428,571 |
| SAFE holder ownership | 8.889 percent | 10.000 percent |
| New investor ownership | 20.000 percent | 20.000 percent |
| Founders and existing holders | 71.111 percent | 70.000 percent |
The new investor holds 20.000 percent either way, so the entire 1.111 point difference comes out of founders and existing holders. The two instruments are not interchangeable at the same cap: the post-money cap that leaves the holder in the same position is the pre-money cap plus the amount raised on the instruments, so a 9,000,000 post-money cap issues exactly the same 1,000,000 shares as an 8,000,000 pre-money cap on 1,000,000 invested.
Every input is encoded in the query string, so a completed scenario is a link. Everything computes in the browser and nothing is sent anywhere.
| Parameter | Meaning | Example |
|---|---|---|
fd | Pre-round fully diluted share count, excluding shares issuable on conversion of the instruments | 8000000 |
pre | Pre-money valuation of the priced round | 12000000 |
raise | New money in the priced round | 3000000 |
safes | Comma-separated instruments, oldest first. Each is amount:cap:discount:type, discount a decimal fraction, type pre, post, or note<r>:<t>. Append ~mfn for a most-favoured-nation election. A cap of 0 means uncapped. | 1000000:8000000:0:post |
pool | New option pool as a decimal fraction, created inside the pre-money share count. Defaults to 0. | 0.1 |
poolbase | pre for a fraction of the enlarged pre-round count, post for a fraction of the post-round count. Defaults to pre. | post |
The reference scenario as a post-money SAFE:
https://venture-capital.wiki/calc/safe/?fd=8000000&pre=12000000&raise=3000000&safes=1000000:8000000:0:post
The same headline terms as a pre-money SAFE:
https://venture-capital.wiki/calc/safe/?fd=8000000&pre=12000000&raise=3000000&safes=1000000:8000000:0:pre
A mixed stack, solved simultaneously:
https://venture-capital.wiki/calc/safe/?fd=8000000&pre=12000000&raise=3000000&safes=500000:10000000:0:pre,1000000:8000000:0:post
A note with a cap, a discount, and eighteen months of 6 percent simple interest:
https://venture-capital.wiki/calc/safe/?fd=8000000&pre=12000000&raise=3000000&safes=1000000:8000000:0.2:note0.06:1.5