Simple Agreements for Future Equity — SAFE notes — have become the default fundraising instrument for pre-seed and seed-stage startups. Created by Y Combinator in 2013, SAFE notes replaced convertible notes as the preferred way to raise early-stage capital without setting a formal valuation. If you’re raising your first round, understanding SAFE notes is essential.
What Is a SAFE Note? How SAFE Agreements Work
A SAFE note is exactly what it sounds like: a simple agreement where an investor gives you money today in exchange for the right to receive equity in the future, typically at your next priced round (Series A). Unlike convertible notes, SAFE notes are not debt — they’re a promise of future equity.
- SAFE notes don’t accrue interest — unlike convertible notes which carry 2–8% interest rates
- SAFE notes have no maturity date — no repayment deadline hanging over your startup
- SAFE notes are not debt — they’re a future equity promise, keeping your balance sheet clean
- SAFE notes are typically 2–5 pages — simple, standardized, and founder-friendly documents
SAFE Note Key Terms: Valuation Cap and Discount Rate
The two most important terms in any SAFE note are the valuation cap and the discount rate. Understanding these terms is critical to knowing how much equity dilution you’re actually taking when you raise on a SAFE.
Valuation Cap: Sets the maximum startup valuation at which the SAFE note converts to equity. If your company’s valuation at the Series A exceeds the cap, the SAFE converts at the cap — giving the investor a better price per share as a reward for investing early.
Discount Rate: Gives the SAFE note holder a percentage discount (typically 15–25%) on the price per share at conversion. Most SAFE notes include a valuation cap, a discount, or both — investors usually convert at whichever gives them the better deal.
Pre-Money vs. Post-Money SAFE Notes: Understanding the Difference
In 2018, Y Combinator updated the SAFE to the post-money version. This was a significant and often misunderstood change that affects how founders calculate dilution from SAFE notes.
Post-money SAFE notes include the SAFE amount and the option pool in the pre-money valuation, which means founders can calculate their exact dilution upfront. With pre-money SAFEs, dilution was harder to predict.
— Y Combinator SAFE Documentation
SAFE Note Conversion Example: How the Math Works
Let’s walk through a concrete SAFE note conversion example to illustrate the difference between pre-money and post-money SAFEs:
Post-Money SAFE Example
You raise $1M on a post-money SAFE note with a $10M valuation cap. At your Series A, the SAFE converts at the $10M cap, giving the investor exactly 10% of the company ($1M ÷ $10M = 10%). Clean, predictable, and easy to model on your cap table.
Pre-Money SAFE Example
With a pre-money SAFE note at a $10M cap and a $5M Series A raise, the investor gets $1M ÷ ($10M + $5M) = 6.67%. The more you raise at the priced round, the less dilution the SAFE investor takes — harder to model in advance
The Biggest SAFE Note Mistake Founders Make
The most common mistake founders make with SAFE notes is raising too much capital on multiple SAFEs with different valuation caps. Each SAFE dilutes you at conversion, and the cumulative math can get surprisingly painful.
Our advice for founders: Before signing any SAFE note, model the conversion scenarios on your cap table. Use a tool like Carta or a simple spreadsheet to understand exactly how much ownership you’re giving up across all outstanding SAFE notes. Your future self will thank you.
