SAFE vs Convertible Note: Which Should You Use?

Understanding the Instruments

A SAFE (Simple Agreement for Future Equity) is a Y Combinator-created instrument that gives investors the right to receive equity in a future priced round. It's not debt — there's no interest rate, no maturity date, and no repayment obligation.

A convertible note is debt that converts to equity at a future priced round. It carries an interest rate (typically 2–8%), a maturity date (typically 18–24 months), and creates a repayment obligation if conversion doesn't happen.

Both instruments defer the valuation discussion to a later round, which is their primary advantage at early stages where valuation is difficult to establish.

When to Use a SAFE

SAFEs are ideal for pre-seed and early seed rounds where speed matters and the raise amount is under $2M. Their advantages:

- No legal negotiation on interest rates or maturity dates - Lower legal costs ($0–$2K vs. $5K–$15K for notes) - No maturity date pressure — the company isn't forced to raise or repay - Standardized terms (YC's post-money SAFE is widely understood)

The key decision with SAFEs is the valuation cap. This is the maximum valuation at which the SAFE converts — effectively setting a ceiling on the price investors pay for their shares.

When to Use a Convertible Note

Convertible notes make more sense when:

- Investors want debt-like protections (interest accrual, maturity date) - The raise is larger ($2M+) and investors expect more structure - You're raising from institutional investors who prefer notes for accounting reasons - You're in a geography where SAFEs aren't well-understood

The interest rate on a convertible note typically adds 2–8% to the investor's effective ownership at conversion. On a 2-year note at 5% interest, that's meaningful dilution that founders often overlook.

The Decision Framework

Ask yourself three questions:

1. How fast do I need to close? If speed matters, SAFE wins. Notes require more negotiation.

2. How sophisticated are my investors? Angels and micro-VCs are comfortable with SAFEs. Some institutional investors prefer notes.

3. What's my timeline to a priced round? If you expect to raise a priced round within 12 months, either works. If it might take 24+ months, a note's maturity date creates pressure you may not want.

Regardless of instrument choice, the preparation work before these conversations determines your leverage. A founder who understands these mechanics and can articulate their reasoning will negotiate better terms than one who relies on their lawyer to explain the documents.