What your SAFE actually converts into
A cap and a discount describe how a SAFE converts, but not what it actually converts into. That takes a calculation, and a post-money SAFE’s own mechanics make one part of it exact: the ownership percentage a cap guarantees does not depend on what your next round ends up pricing at.
The calculator below models one Canadian SAFE or convertible note converting on its own. The article underneath explains the mechanics, including the one thing that changes once more than one SAFE is outstanding.
SAFE Dilution Calculator
Enter your SAFE or convertible note terms and see what it actually converts into: the ownership percentage, the share count, and what that does to everyone else on the cap table.
Recalculates as you type. No account, no email required.
The most the investor's stake is worth if the company's post-money valuation at conversion is at or above this number.
Every issued share, plus every outstanding option and warrant, plus the unallocated option pool. Not this instrument, not any other SAFE, not the new round.
$250,000 into a $8,000,000 post-money cap. This is fixed the moment the SAFE is signed — the whole design of a post-money instrument is that this percentage does not move regardless of what your next round actually prices at.
322,581 shares against 10,000,000 shares outstanding today.
If you have more than one SAFE or note outstanding at different caps, they convert together, not one at a time, and the math becomes a system to solve rather than a formula — stacked SAFEs routinely dilute founders worse than this kind of single-instrument estimate suggests. That reconciliation is exactly what a lawyer or your cap table software does at the priced round.
A licensed Canadian lawyer checks the actual math against your signed documents before your next round closes.
This models your SAFE. The Startup Legal Readiness Score checks whether the instrument itself, and everything around it, is actually papered properly.
This tool gives general information, not legal or financial advice, and using it does not create a solicitor-client relationship. It models a single instrument converting on its own; a real cap table with more than one SAFE or note outstanding needs the reconciliation a lawyer or your cap table software does.
Cap, discount, and MFN, plainly
The terms that actually decide what a SAFE converts into.
| Term | What it actually is | When it shows up |
|---|---|---|
| Valuation cap | The maximum post-money valuation the investor's conversion price is calculated against. Ownership works out to investment / cap, fixed the moment the instrument is signed. | Present on almost every Canadian pre-seed and seed SAFE. Protects the investor if the company's value rises fast before the next round. |
| Discount | A percentage off the priced round's actual per-share price. Only worth something once a round happens and sets a price. | Common alongside a cap as a floor, or on its own in a bridge ahead of a round that is expected imminently. |
| Cap and discount together | Both apply, and the investor converts at whichever price is lower, meaning whichever gives them more shares. | The most common structure once a company has some traction and a credible near-term valuation. |
| MFN (most favoured nation) | A clause letting an earlier investor step up to a later investor's better terms if the company issues a more generous SAFE afterward. | Common on the first money in, before the company has a clear sense of what the market will bear. |
Questions founders ask
That is the specific design of the post-money SAFE structure most Canadian pre-seed and seed rounds now use. The investor's percentage is fixed at investment divided by the cap the moment the instrument is signed, and it stays fixed regardless of what the eventual priced round values the company at. A pre-money SAFE, the older structure, worked differently, which is part of why the market moved away from it.
They convert together at the priced round, not one after another, and the math becomes a system of interdependent equations rather than a single formula, because each SAFE's conversion price is defined against a company-wide share count that includes every other SAFE also converting. This is exactly the reconciliation a lawyer or cap table software runs at the priced round, and it is why this calculator is deliberately scoped to one instrument at a time rather than approximating a stack.
Close, with one real difference: a note accrues interest and has a maturity date, so the amount that actually converts is the principal plus whatever interest has accrued, not just the principal. Once that effective amount is worked out, the cap and discount mechanics work the same way as a SAFE.
Not as it comes. A YC-style SAFE is written for a Delaware C-corp and does not address Canadian prospectus exemptions under NI 45-106, and a stack of US investors on the cap table can put a company's Canadian-controlled status, and the SR&ED credit that depends on it, at risk. The underlying cap-and-discount mechanics this calculator models are the same either way; the surrounding legal structure is not.
Last reviewed 2026-08-26 by Brooke Ash, Head of Legal, Ruby. This tool gives general information, not legal or financial advice, and using it does not create a solicitor-client relationship. It models a single instrument converting on its own; a real cap table with more than one SAFE or note outstanding needs the reconciliation a lawyer or your cap table software does.
Ready to get your actual cap table checked?
Tell us about your matter and a Ruby lawyer will follow up directly.