SAFEs in plain founder language
SAFE terms are easy to sign and easy to misunderstand. Founders need to model cap, discount, pre/post-money, MFN, and conversion together.
A founder I will call the median case signs a $500k SAFE at a $10M post-money cap because the angel offered it, the template was free, and three other founders said it was standard. A week later a cofounder asks one question: "So how much of the company did we just sell?" The founder opens the document, sees the word "cap," sees the word "discount," and cannot answer. Not because they are not smart. Because nobody made them do the arithmetic before they signed, and the SAFE is designed to make signing feel like nothing happened.
That feeling is the trap. A SAFE moves no shares on the day you sign it. No ownership column changes, no board seat, no price. It looks like a loan that never has to be repaid, which is roughly how it gets sold. What actually happens is that you have promised a slice of a future round to an investor, and the size of that slice is fixed by terms you agreed to today and will not feel until conversion, sometimes two years and three SAFEs later. By then the slices have stacked, and founders open a pre-priced-round model for the first time and find they sold 28% of the company in pieces they each thought were small.
What founders get wrong about SAFEs
The first mistake is treating the cap as a valuation. It is not. A SAFE has no price. The cap is the most you will pay later, in the sense that it sets the worst conversion price for the investor and the best protection for them. Founders hear "$10M cap" and think "we are worth $10M." Investors hear "$10M cap" and think "if you raise at $30M, I convert as if you were worth $10M, so I get three times the shares my money would otherwise buy." The cap is not your valuation. It is the investor's floor on ownership.
The second mistake is stacking SAFEs without modeling them together. Each one feels independent. A $250k here, a $500k there, an angel who wanted in for $50k. Individually none of them seems to move the needle. But SAFEs do not convert one at a time against fresh ownership. They all convert at the same priced round, against the same pre-money, and they dilute you and each other simultaneously. Four "small" SAFEs at four different caps is a cap table you cannot read until a lawyer builds the conversion waterfall, usually the week you are trying to close your seed.
The third mistake is not knowing whether you signed pre-money or post-money. This sounds like a footnote. It decides who absorbs the dilution from every SAFE that comes after. The shift from the old pre-money SAFE to the post-money SAFE that became standard after 2018 quietly moved real ownership from founders to investors, and most founders signing today have never been told the difference exists.
The framework: a SAFE is four decisions, not one document
Stop reading the SAFE as a contract to skim. Read it as four numbers you are setting. Everything else in the document is boilerplate.
The cap. The valuation ceiling at which the SAFE converts. Lower cap, more of the company to the investor. This is the single most important term and the one founders negotiate least.
The discount. A percentage off the next round's price, typically 10–20%. It rewards the investor for being early. A SAFE can have a cap, a discount, or both, and when it has both the investor takes whichever gives them more shares.
Pre-money vs post-money. This decides whether the cap counts the other SAFEs or not. Under a post-money SAFE, the investor's percentage is locked in after all SAFEs convert, so every future SAFE and the priced round dilute the founders, not the earlier SAFE holders. Post-money is cleaner to calculate and worse for founders. Pre-money shares the dilution but is harder to model. Almost every SAFE today is post-money, so assume it unless the document says otherwise.
MFN (most favored nation). A clause that lets an investor with no cap or a high cap automatically adopt the best terms you give any later SAFE holder. If you give a friendlier cap to someone next month, an MFN investor silently inherits it. Useful for them, a hidden liability for you if you sign one early and forget it exists.
Two more terms ride along and matter at conversion. Pro rata gives the investor the right to invest again in your priced round to maintain their percentage. Side-letter pro rata on a small SAFE can hand a tiny early check an outsized claim on your seed allocation. And the conversion trigger defines what counts as the priced round that converts the SAFE, plus what happens to the SAFE in an acquisition before any priced round, where founders are sometimes surprised to find the SAFE converts at the cap and takes a real bite of the exit.
A worked example so the cap stops being abstract
Say you raise $1M total on post-money SAFEs at a $10M post-money cap. Then you raise a $3M priced seed at a $20M pre-money. Here is what the cap actually did.
| Without understanding the cap | What actually happens | |
|---|---|---|
| What "$10M cap" felt like | "We're worth $10M, fine" | Investor's ownership is locked at the cap, not the round price |
| SAFE investors' price | The $20M round price | The $10M cap price, roughly half |
| Effective shares to SAFE holders | ~5% ($1M of $20M) | ~10% ($1M of $10M post) |
| Who absorbs the gap | Assumed shared | Founders, because it is post-money |
The SAFE investors put in $1M and, because the company grew into a real round, end up with about 10% instead of the 5% their money would buy at the actual round price. That extra 5% does not come from the new seed investors. Under a post-money SAFE it comes from the founders' column. The cap was not a formality. It was a 5% transfer that nobody felt until the seed closed.
This is why the move is not "negotiate harder." The move is to build the conversion waterfall before you sign each SAFE, so the cap is a number you chose with eyes open rather than a surprise your lawyer reveals later.
The artifact: SAFE term glossary and pre-signing decision checklist
Keep this next to any SAFE before you sign it.
Glossary, in founder terms
- Cap: the valuation that decides the investor's worst-case price. Lower = more of your company to them. The number that matters most.
- Discount: percent off the next round's price, usually 10–20%. Rewards being early.
- Post-money SAFE: the investor's percentage is fixed after all SAFEs convert. Future SAFEs and the round dilute you, not them. Today's default.
- Pre-money SAFE: dilution from later SAFEs is shared. Rare now, founder-friendlier, harder to model.
- MFN: the investor auto-adopts the best terms you later give anyone else. Watch for this on uncapped or high-cap early checks.
- Pro rata: the right to invest again in your priced round to keep their percentage. Check whether it lives in the SAFE or a side letter.
- Conversion trigger: what counts as the priced round that converts the SAFE, and what the SAFE does in an acquisition before any round.
Decision checklist, before you sign
- Can I state, in one sentence, what percentage this SAFE converts to if I raise my next round at 2x the cap? If not, I am not ready to sign.
- Is it pre-money or post-money? (Assume post unless it says pre.)
- What is the total of all SAFEs outstanding, modeled converting together at this cap? Not each alone.
- Does any existing SAFE carry an MFN that this new term would trigger?
- Cap, discount, or both? If both, which one gives the investor more, and have I priced that?
- Is there pro rata, and does it live in a side letter I will forget?
- What happens to this SAFE if we get acquired before a priced round?
- Have I run the full waterfall, including this SAFE, against a realistic next-round price?
If you cannot answer 1, 3, and 8 with numbers, the SAFE is not ready to sign, no matter how standard the template looks.
Questions to ask counsel and the investor
To your lawyer: build me the conversion waterfall across every SAFE I have signed, at a low, base, and high next-round price, and show me my founder ownership at each. Flag any MFN, side-letter pro rata, or non-standard conversion trigger.
To the investor, plainly: is this pre or post-money, cap and discount or just one, and do you expect pro rata? These are normal questions. An investor who treats them as a sign of inexperience is telling you something about how the relationship will go.
Where RoundOS fits
The reason SAFE terms get away from founders is not the math. It is that the terms live in five places: a signed PDF in email, a number in a lawyer's draft, a cap an angel mentioned on a call, a side letter nobody filed, and a memory of what you promised the seed lead. By the time you model the round, reconstructing what you actually agreed to is its own project.
RoundOS keeps every financing conversation connected to the documents and people it came from. The SAFE PDF, the email where the cap was agreed, the call notes, and the follow-up thread sit on the same investor record, so when you sit down to model the priced round you are reading from one place instead of stitching the terms back together from memory. The terms stop being scattered, and the next move, whether that is modeling the waterfall or going back to renegotiate a cap before it stacks, becomes obvious.
Run the SAFE check before you sign.
Pull every SAFE you have signed into one place and model them converting together at your expected next round. If you cannot do that in an afternoon, that is the problem RoundOS solves first. Upload your financing threads and let it assemble the terms onto one investor record.