What are convertible notes and SAFE agreements?

Key takeaways

• A convertible note is a short-term loan that converts into equity, usually with interest and a maturity date.

• A SAFE is not debt, no interest, no repayment date, no maturity.

• Both instruments delay setting a company valuation until a priced round or other triggering event.

• A valuation cap and a discount decide how much equity an investor gets at conversion.

• Stacking multiple SAFEs or notes with different terms can cause more dilution than a founder expects.

• The right choice depends on investor preference, deal speed, and how the terms play out on the cap table.

What is a convertible note?

A convertible note is a loan a company takes from an investor. Under the agreement, the loan converts into equity at a later date, typically at the next priced funding round, instead of being repaid in cash.

Because it is debt, a convertible note usually includes an interest rate and a maturity date. If the company has not raised a priced round by the maturity date, the agreement terms determine what happens next: the note may convert at an agreed valuation, extend, or, in some cases, require repayment.

What is a SAFE agreement?

A SAFE is an agreement where an investor puts in money today in exchange for the right to receive equity later, usually when the company raises a priced round. It carries no interest and no repayment date because it is not a loan.

A SAFE was originally created by Y Combinator as an alternative to convertible notes, and is now the default instrument used across most US accelerators and seed-stage rounds, since it requires less negotiation and lower legal cost to execute than a note. A SAFE is a security under US federal law, and companies typically sell it under an exemption from SEC registration requirements (commonly Regulation D), though a company should confirm the applicable exemption with counsel for each raise.

Convertible notes vs SAFEs: Key differences

Both instruments delay the valuation conversation, but they differ in legal form, cost, and what happens if a priced round never materializes. The table below compares the main points side by side. 

Pros and cons of convertible notes and SAFEs

Convertible notes

Pros:

1. A familiar debt structure that most investors and lawyers already understand.

2. A fixed maturity date that forces a conversion decision instead of leaving the raise open-ended.

3. Interest gives the investor a modest return if conversion is delayed.

4. Terms (interest rate, maturity date, repayment conditions) are negotiable and can be tailored to the raise.

5. Widely recognized across investor types, including those less familiar with newer instruments.

Cons:

1. Legal documentation costs more to draft and negotiate than a SAFE.

2. A missed maturity date can create repayment pressure or disputes.

3. Interest accrual adds a small amount of dilution to the company.

4. Debt on the balance sheet can affect financial ratios and future borrowing.

5. Negotiating individual terms takes more time than signing a standard template.

SAFEs

Pros:

1. Faster and cheaper to draft than a convertible note.

2. No repayment obligation, since a SAFE is not debt.

3. No maturity pressure on the founder to force a decision on a fixed date.

4. A standard, widely used template reduces negotiation back-and-forth.

5. No interest accrual, which keeps the eventual dilution calculation simpler.

Cons:

1. No legal deadline forces conversion, so a SAFE can remain outstanding for years.

2. Some traditional lenders and later-stage investors are less familiar with the format.

3. Stacking several SAFEs with different terms can make total dilution harder to track.

4. Fewer contractual protections for the investor compared to a note.

5. Limited legal precedent compared to conventional debt instruments.

When to use a convertible note vs a SAFE

Combine both, if needed; some companies run a SAFE for early angels and a note for a later bridge, though this requires careful cap table modeling since each converts on its own terms.

• Use a SAFE for a fast, low-cost pre-seed or seed raise with angel investors or an accelerator, where speed and low legal cost matter more than a fixed deadline.

• Use a convertible note when investors want a debt structure with interest and a fixed deadline, or when a bridge round needs a hard conversion trigger tied to a specific date.

Do investors prefer a SAFE or a convertible note?

Preference varies by investor type. Angel investors and seed funds connected to accelerators are generally comfortable with SAFEs, since the format is fast, standardized, and keeps legal costs low. Later-stage investors, family offices, and lenders used to formal debt protections more often prefer a convertible note, since it gives them contractual repayment rights and an interest return if the company doesn't raise a priced round on schedule. The decision depends on what protections the investor's legal team requires and how the round is structured.

Common mistakes founders make with notes and SAFEs

1. Stacking too many SAFEs with different caps without modelling the combined dilution, then being surprised at the priced round.

2. Ignoring the maturity date on a convertible note until it has already passed.

3. Treating a SAFE as free money, every SAFE is a claim on future equity, and it counts against a founder's ownership the same as a priced round would.

4. Missing an MFN clause carried by an earlier investor, which can quietly change terms across an entire raise.

5. Confusing pre-money and post-money SAFEs, leading to a dilution estimate that turns out wrong once the round closes.

6. Assuming a SAFE is automatically exempt from securities registration without confirming the exemption (typically Regulation D) applies to that specific raise.

Tax treatment for US founders and investors

Tax treatment differs for the two instruments and should be confirmed with a certified public accountant (CPA) for each specific raise, but the general shape looks like this:

• Convertible notes can trigger original issue discount (OID) rules under the IRS code, meaning an investor may owe tax on imputed interest income before the note actually converts, depending on the note's terms.

• SAFEs, having no interest, generally create no taxable event for the investor until conversion into shares, though this depends on the specific SAFE structure and the entity's tax classification.

• Qualified small business stock (QSBS) treatment under IRC Section 1202 can give investors a significant capital gains exclusion once SAFE or note proceeds convert into qualifying stock, this is a common reason investors ask about entity structure before funding a US startup.

• Founders issuing either instrument should confirm 83(b) election timing and QSBS eligibility with a CPA, since these decisions carry strict filing deadlines.

Conclusion

Convertible notes and SAFEs both give US early-stage companies a way to raise money before setting a formal valuation, but they carry different legal weight. A note is debt, with interest and a maturity date. A SAFE is not debt and has neither.

The terms in a note or SAFE, the valuation cap, the discount, the conversion trigger, decide how much of the company a founder still owns once a priced round closes. A founder who signs several of these agreements without tracking how they interact can end up with far less ownership than expected, at the exact moment it becomes visible to every investor on the cap table. Understanding how each instrument converts, and modelling it before signing, is what keeps that outcome predictable rather than a surprise at the next round.

How Qapita can help

Tracking multiple SAFEs and convertible notes by hand, each with a different cap or discount, makes it easy to lose sight of actual dilution until a priced round forces the number into view. Qapita's cap table management platform models these conversions in advance, so a founder can see exactly how ownership shifts under each scenario before agreeing to new terms.

Book a demo with Qapita to see your own cap table modelled before your next raise.

FAQ

1. What is convertible debt?

Convertible debt is a loan that turns into equity later instead of being repaid in cash. A convertible note is the most common form, it carries interest and a maturity date, and converts into shares at the terms set in the agreement.

2. Is a convertible note the same as a convertible promissory note?

‍Yes. "Convertible note" and "convertible promissory note" refer to the same instrument, a written promise to repay a loan that converts into equity instead of cash, under the terms set in the agreement.

3. How does a convertible note work?

‍An investor puts in money as a loan. The agreement sets an interest rate, a maturity date, and usually a valuation cap or discount. When the company raises a priced round, the note converts into shares at the cap, the discount, or the new round's price, whichever gives the investor the better terms.

4. Do venture capital firms use SAFEs?

‍Yes, particularly at the seed stage. Angel investors and seed funds connected to accelerators like Y Combinator commonly use SAFEs for speed and lower legal cost. Later-stage VC firms doing bridge rounds more often prefer a convertible note for its fixed deadline and interest terms.

5. Is a SAFE debt or equity?

A SAFE is neither, at signing. It is a contract for future equity, no shares exist yet, and no repayment is owed. It converts into actual shares only once a triggering event occurs, most commonly a priced equity round, an acquisition, or a dissolution.

6. Why does a SAFE have no interest or maturity date?

A SAFE carries no interest rate because it is not a loan, there is no principal balance accruing a return for the investor while the agreement remains outstanding. It also has no maturity date, since a SAFE has no deadline forcing repayment or conversion. A SAFE converts when a triggering event happens, not on a fixed date, typically a priced equity round, an acquisition, or a dissolution. Until one of those events occurs, a SAFE can remain outstanding with no obligation on either party, in some cases for several years.

7. What are convertible securities?

Convertible securities are financial instruments that start as one form of investment and later convert into equity, under terms set out in the agreement at signing. Convertible notes and SAFEs are the two most common types used in early-stage startup financing, a convertible note converts from debt into shares, while a SAFE converts from a right to future equity into shares. Both delay the question of company valuation until a triggering event, most often a priced funding round.