SAFE vs. Convertible Note: What's the Difference?

Most seed and pre-seed rounds in the US close on either a SAFE or a convertible note. Both are ways to raise money now without setting a formal company valuation — the price gets determined later, at your priced Series A round. But they're meaningfully different instruments, and using the wrong one can create headaches.

What a SAFE Is

A SAFE (Simple Agreement for Future Equity) is not a loan. It's an agreement that the investor gives you money today, and in exchange gets the right to purchase equity in the future, at a discount, when you raise a priced round.

Y Combinator created the SAFE in 2013 and made the standard documents freely available. It has since become the default instrument for early-stage rounds in the US, particularly at pre-seed.

Key characteristics:

• No interest rate
• No maturity date (it doesn't "expire")
• No repayment obligation
• Converts to equity at your next priced round

Because there's no maturity date and no interest, a SAFE is simpler and cleaner than a note. There's nothing to renegotiate if your round takes longer than expected.

What a Convertible Note Is

A convertible note is a loan — it has a principal amount, an interest rate (typically 4–8%), and a maturity date (usually 12–24 months). At maturity, the note either:

1. Converts to equity (at the next priced round, with the cap and discount applied), or
2. Must be repaid if no conversion event has occurred

The loan structure creates obligations that SAFEs don't. If you haven't raised a priced round by the maturity date, you and the noteholder have to renegotiate — extend the note, convert to equity at a negotiated valuation, or technically face repayment (which almost never happens in practice, but creates legal awkwardness).

Key characteristics:

• Accrues interest (adds to principal at conversion)
• Has a maturity date
• Is technically debt until conversion
• More negotiating points than a SAFE

The Shared Mechanics: Caps, Discounts, and MFN

Both instruments use these core features to give early investors a better deal than later investors:

Valuation Cap

The cap is the maximum valuation at which an investor converts, regardless of how high your Series A is priced.

Example: You raise on a SAFE with a $6M cap. Your Series A is priced at $20M pre-money. The SAFE investor converts as if the price was $6M — so they get roughly 3.3x more equity than if they'd waited and invested at the Series A price.

The cap rewards early investors for taking more risk. Setting it correctly matters: too low and you're giving away too much at Series A; too high and early investors get less of the discount they expected.

Discount Rate

Separately from the cap, many SAFEs and notes include a discount rate (typically 15–25%). This means the investor converts at a percentage off whatever the Series A price is.

Example: 20% discount, Series A priced at $10/share. The SAFE investor converts at $8/share.

In practice, if you have both a cap and a discount, investors convert using whichever is more favorable to them. Founders often include one or the other — both is common in notes, less common in SAFEs.

MFN Clause (Most Favored Nation)

An MFN clause means that if you subsequently issue a SAFE or note on better terms to another investor, the original investor gets to adopt those better terms.

This protects early investors from being disadvantaged by later, lower caps or higher discounts issued to other seed investors. It's commonly used on SAFEs with no cap (uncapped SAFEs), where the MFN ensures the investor gets the best terms offered to anyone in the round.

Key Differences Summary

| Feature | SAFE | Convertible Note | |---|---|---| | Is it debt? | No | Yes | | Interest? | No | Yes (4–8%) | | Maturity date? | No | Yes (12–24 months) | | Repayment risk? | None | Theoretical if no conversion | | Complexity | Low | Higher | | Standardization | Very high (YC template) | Variable | | Negotiating points | Few | More |

Which Should You Use?

Use a SAFE when:

• You're a US-based company raising a pre-seed or seed round
• You want simplicity and speed (close in days, not weeks)
• You're using the YC standard template (investors know it, lawyers don't need to reinvent it)
• You're doing a rolling close — adding investors over weeks or months

Use a convertible note when:

• Your investors or lawyers prefer it (older angels and some institutional investors still prefer notes)
• You're in a jurisdiction where SAFEs aren't standard
• You want a maturity date as a forcing function for a priced round (some founders use this deliberately)
• Your investors specifically request it

Post-Money SAFEs vs. Pre-Money SAFEs

Y Combinator updated the standard SAFE to post-money in 2018. This is now the default:

• Post-money SAFE: The cap is based on post-money valuation (after the SAFE investment is included). This makes dilution calculations clearer and more predictable.
• Pre-money SAFE: Older version; the cap is based on pre-money valuation. If you issue multiple pre-money SAFEs, dilution calculations become complicated and founders often give away more than they realize.

Always use post-money SAFEs unless there's a specific reason not to.

A Practical Note on Negotiations

The cap is the primary thing you'll negotiate. In current markets (US, 2025–2026), typical seed-stage caps range from $5M–$15M depending on team, traction, and sector. Pre-seed caps range from $2M–$8M.

Know what comparable companies are raising at before you sit down. And remember: a lower cap feels painful now but is typically a smaller amount of money than the equity you'll give up at a high valuation if the company succeeds.