SAFE Note vs. Convertible Note: What They Are, How They Differ, and Which to Use
- Giorgi Meskhi
- Aug 9
- 9 min read
In Q1 2026, convertible notes hit a record low of just 7% of US pre-seed rounds, according to Carta’s State of Pre-Seed Q1 2026. SAFEs took the other 93%. That is not a close debate. For most US founders raising before a priced round, the instrument question has largely been settled by the market.
But understanding why SAFEs won - and the specific situations where a convertible note still makes sense - is what separates a founder who signs the right instrument from one who signs the wrong one and discovers the consequences two years later at a priced round.
We have reviewed cap tables across more than 600 fundraising engagements at RunwayTeam. This guide explains what both instruments are, how they differ mechanically, and the decision framework we use to help founders make a choice.
What Is a SAFE Note?
A SAFE - Simple Agreement for Future Equity - is a contractual right to receive equity in a startup at a future priced round. It is not debt. It does not accrue interest, carries no maturity date, and creates no obligation on the company to repay anything. The investor hands over capital today; in return, they receive shares when the company closes a priced equity round, at terms set in the SAFE.
YC created the SAFE in 2013 as a simpler, faster alternative to convertible notes for early-stage financing. The original version was a pre-money SAFE. In 2018, YC introduced the post-money SAFE as the updated standard. It is the version nearly every US founder uses today.
A SAFE has three key terms. Understanding them is the foundation of any instrument conversation.
Valuation cap
The maximum valuation at which the SAFE converts to equity. If the company raises a priced round at a valuation above the cap, the SAFE holder converts at the lower cap valuation - giving them a better price per share than new investors pay. This is the investor’s reward for taking early risk. For founders, a lower cap means more dilution at conversion. A higher cap means less.
Discount rate
An optional term that gives the SAFE holder a percentage discount on the share price at conversion. A 20% discount is the standard when a discount is included - used in 63% of discounted SAFEs according to Carta. Many post-money SAFEs today use only a cap, with no discount. “Cap only” has become the dominant structure precisely because it is simpler and cleaner on the cap table.
MFN clause
Most favored nation. If the company issues a future SAFE on better terms, the MFN clause gives the current SAFE holder the right to upgrade to those better terms. Common in early angel SAFEs before a cap is agreed. It is a protective clause for the investor, not for the founder.
Post-Money vs. Pre-Money SAFE: The Detail Most Founders Miss
This is the distinction that creates the most confusion - and the most expensive surprises at conversion. If you only remember one technical difference about SAFEs, make it this one.
A post-money SAFE sets the valuation cap on the post-money valuation - meaning the SAFE money is already included in the cap. A $500K check on a $5M post-money cap gives the investor exactly 10% of the company ($500K ÷ $5M). That percentage is fixed and predictable, regardless of how many other SAFEs are stacked on top.
A pre-money SAFE sets the cap on the pre-money valuation. The same $500K check on a $5M pre-money cap converts at $5.5M post-money - giving the investor 9.1%. So far so similar. But stack a second $500K SAFE on top, and both investors’ ownership percentages shrink unpredictably, because the pre-money cap does not account for the other SAFEs in the stack.
Post-money SAFEs have grown from just over 60% of all SAFEs in 2021 to nearly 90% today, per Carta’s annual pre-seed data. Pre-money SAFEs are effectively legacy instruments now. If someone hands you a pre-money SAFE in 2026, ask why.
What Is a Convertible Note?
A convertible note is debt that converts to equity. The investor loans the company money, which accrues interest until the note converts to shares at the next priced round or at maturity. Unlike a SAFE, a convertible note has two structural features that create real obligations for the company: an interest rate and a maturity date.
The median interest rate on convertible notes was 7% per annum in Q1 2025, down slightly from a peak of 8% in mid-2024, according to Carta. Maturity is typically 18-24 months. When the note matures without a priced round, the company and investor must renegotiate - usually by extending the note or triggering a conversion on agreed terms. That negotiation is rarely comfortable for either side.
Convertible notes carry the same cap and discount mechanics as SAFEs. The difference is the debt wrapper around them. At conversion - triggered by a priced round or the maturity date - the outstanding principal plus accrued interest converts into preferred shares.
One practical note: because a convertible note is technically debt, it appears on the company’s balance sheet as a liability until it converts. SAFEs, not being debt, do not. This matters for accounting purposes and for investors who scrutinize the balance sheet during diligence.
SAFE vs. Convertible Note: The Comparison
Six factors that determine which instrument fits which situation.
When to Use a SAFE
A SAFE is the right instrument in most US pre-seed situations. Here are the three scenarios where it is the clear default.
You are raising from US-based angels or early-stage funds
The post-money SAFE is the market standard for a reason: US investors are familiar with it, lawyers can close it in days rather than weeks, and the YC template is free. If your investors are US-based and early-stage, defaulting to a post-money SAFE is almost always the right call. The valuation cap you negotiate is the strategic lever - the instrument itself should not be the subject of debate.
You want to move quickly
A SAFE closes faster than a convertible note because there are fewer terms to negotiate. No interest rate, no maturity date, no conversations about what happens if the company misses the priced round. For a founder managing an angel round across multiple investors, the speed advantage is material.
You are stacking multiple smaller checks
Many pre-seed rounds are assembled from several $25K-$250K checks rather than one large institutional commitment. The post-money SAFE handles stacking cleanly - each investor knows exactly what percentage they own, and the percentages do not interact. Stack pre-money SAFEs at the same cap and the math gets messy fast. This is also why modeling your cap table before issuing your third SAFE is not optional - it is the only way to know what you are actually giving away in aggregate.
When a Convertible Note Makes More Sense
Convertible notes are not obsolete - they are niche. Three specific situations where they remain the better fit.
Your investors are outside the US
International investors - particularly in Europe, Asia, and the Middle East - are often more comfortable with debt instruments than with SAFEs. The SAFE is a US construct; its legal standing is less settled outside of US jurisdiction. If your lead investor is non-US and their legal team is unfamiliar with SAFEs, the friction of educating them may cost more than simply using a convertible note that they already understand.
You want a structural deadline on the next priced round
A convertible note’s maturity date, usually 18-24 months out, creates a natural forcing function. If the company has not closed a priced round by maturity, something has to happen: an extension, a conversion, or a hard conversation. Some founders find this useful as a commitment device - a built-in date that focuses both the company and the investors on advancing the round. A SAFE has no equivalent pressure.
Your investors specifically require it
Some investors - particularly in biotech, medical devices, and energy, sectors that have historically leaned on notes - prefer the debt structure for internal fund accounting reasons. Carta’s Q3 2025 State of Pre-Seed data shows these industries still show the highest representation of convertible notes among all sectors, even as SAFEs have gained ground there too. If your investor requires a note and the deal is otherwise right, the instrument is not a reason to walk away.
How Both Instruments Appear on Your Cap Table
Before conversion, neither a SAFE nor a convertible note appears on the cap table as a shareholder. Both sit as potential dilution obligations - commitments that will become shares at a future event, recorded in the notes of the fully diluted cap table. This is the version investors want to see when they are evaluating your round. We cover what “fully diluted” means and how to read it in our cap table guide.
At conversion - triggered by a priced round closing - both instruments generate new preferred shares. For a SAFE, the number of shares is determined by the post-money cap (or discount rate, if lower). For a convertible note, the principal plus accrued interest converts at the cap or discount, meaning the investor gets slightly more shares than they would have on day one because of the interest that has been building.
This is where stacking matters. A single $500K post-money SAFE at a $5M cap is simple: 10% converts at the priced round. Three SAFEs at three different caps, plus a convertible note with 18 months of accrued interest, converting simultaneously at a seed round - that conversion math requires a model.
If you have not modeled what your SAFE stack converts to before your seed round closes, you are negotiating the seed round’s dilution blind. The financial model that shows pre-seed instrument conversion alongside the new seed dilution is the document that makes the priced round legible before you sign it.
Common Mistakes with Both Instruments
Using a pre-money SAFE in 2026 without understanding why. If you are signing a pre-money SAFE today, it should be a deliberate choice, not a default. Make sure you understand how it interacts with any other SAFEs in the stack, and run the conversion math before you sign.
Stacking multiple SAFEs at different caps without modeling the aggregate. Each SAFE converts at its own terms, but all of them convert at the same priced round. The combined dilution is almost always higher than founders expect when they look at each SAFE in isolation. Run a pro forma cap table before issuing a second or third SAFE.
A convertible note maturity that arrives before the next priced round. A note maturing without a priced round in sight forces a negotiation the company rarely wins. Either extend - which signals weakness - or trigger automatic conversion at terms that may not be favorable. If you use a convertible note, your round timeline needs to fit inside the maturity window with room to spare.
Ignoring MFN clauses on early SAFEs. If you issue a SAFE with an MFN clause and later issue a second SAFE on better terms - lower cap, higher discount - the MFN gives the first investor the right to upgrade. Founders often forget this until they are in the middle of the second close and discover the first investor is watching.
No pro-rata rights negotiated on early SAFEs. Pro-rata rights give early investors the right to maintain their ownership percentage in future rounds by participating in those rounds. Most early SAFE investors will ask for this. Whether you grant it depends on the investor and the deal - but it should be a deliberate decision, not an oversight.
FAQs
What is a SAFE note?
A SAFE (Simple Agreement for Future Equity) is a contractual right to receive equity in a startup at a future priced round. It is not debt - it does not accrue interest or carry a maturity date. In exchange for capital today, the SAFE holder receives shares when the company closes a priced equity round, on terms set by the SAFE's valuation cap and discount rate.
What is the difference between a SAFE and a convertible note?
A SAFE is not debt. A convertible note is. A convertible note accrues interest, has a maturity date, and creates a legal repayment obligation if not converted. A SAFE has none of those features - it simply sits as a potential dilution obligation until the next priced round triggers conversion. In Q1 2026, SAFEs accounted for 93% of US pre-seed rounds, while convertible notes accounted for 7%.
Which is better for founders: a SAFE or a convertible note?
For most US-based pre-seed and seed founders, a post-money SAFE is simpler, faster, and more founder-friendly. It has fewer negotiated terms, closes in days rather than weeks, and uses a standardized YC document. Convertible notes make more sense when investors are non-US-based, when a specific industry preference favors notes, or when a maturity deadline serves a strategic purpose for both parties.
What is the difference between a post-money SAFE and a pre-money SAFE?
A post-money SAFE calculates the investor’s ownership based on the post-money valuation cap - the cap already includes the SAFE money. A $500K check on a $5M post-money cap gives the investor exactly 10%, and that figure stays predictable even if other SAFEs are stacked. A pre-money SAFE calculates ownership on the pre-money valuation, which makes the final percentage less predictable when multiple SAFEs convert at the same priced round. YC introduced the post-money format in 2018; it is now the near-universal standard.
Does a SAFE or convertible note appear on the cap table right away?
Neither appears as a shareholder on the cap table before conversion. Both show up as potential dilution obligations in the fully diluted notes - they represent shares that will exist after the next priced round triggers conversion. At that point, the SAFE or note converts into preferred shares, and the holder appears as a shareholder for the first time.
Can you use multiple SAFEs at different valuation caps?
Yes, and many founders do. But stacking SAFEs at different caps without modeling the combined conversion is one of the most common early-stage cap table mistakes. Each SAFE converts on its own terms, and the combined dilution in the priced round is almost always higher than founders expect when evaluating each SAFE in isolation. Run a pro forma cap table model before issuing a second or third SAFE.
The Conversion Math on a Stacked SAFE Round Is Not Simple Arithmetic
RunwayTeam builds the financial model that shows founders exactly what their pre-seed instruments convert to at the priced round - before they sign the seed term sheet.
