SAFE Note Calculator
Calculate how a SAFE note converts into equity. Compare valuation cap vs discount routes and see your resulting ownership percentage.
Quick Answer
A SAFE converts at the lower of: Investment / Cap * Pre-money shares (cap route) or Price * (1 - Discount%) (discount route). The investor gets whichever produces more shares.
Calculate SAFE Conversion
Enter your SAFE terms and the next round's pre-money valuation.
About This Tool
The SAFE Note Calculator helps founders, investors, and startup advisors understand how a Simple Agreement for Future Equity converts into ownership at a priced round. By inputting your investment amount, valuation cap, discount percentage, and the next round's pre-money valuation, you can instantly see the conversion price, number of shares issued, and resulting ownership percentage through both the cap and discount routes.
Understanding SAFE Notes
SAFE notes were introduced by Y Combinator in 2013 as a simpler alternative to convertible notes for early-stage startup fundraising. Unlike convertible notes, SAFEs carry no interest rate and have no maturity date, making them cleaner instruments for both founders and investors. The core idea is straightforward: an investor gives a startup money now in exchange for the right to receive equity later, when the company raises a priced round. The terms of that future conversion are governed by the valuation cap and discount rate specified in the SAFE agreement.
How Valuation Caps Work
A valuation cap sets the maximum valuation at which the SAFE investment converts into equity. If the company's next priced round has a pre-money valuation higher than the cap, the SAFE investor converts as if the valuation were equal to the cap, resulting in a lower price per share and more ownership. For example, if an investor puts $500,000 into a SAFE with a $5M cap and the Series A pre-money valuation is $20M, the investor converts at the $5M valuation rather than the $20M valuation, effectively receiving four times more shares per dollar than the Series A investors. The cap rewards early investors for taking risk before the company had significant traction.
How Discount Rates Work
The discount rate provides a percentage reduction on the price per share paid by investors in the next priced round. A 20% discount means the SAFE holder pays 80% of the Series A price. When a SAFE includes both a valuation cap and a discount, the investor benefits from whichever mechanism produces a lower conversion price (and therefore more shares). In practice, the cap tends to be more valuable when the company grows significantly between the SAFE issuance and the priced round, while the discount is more valuable when growth is modest and the priced round valuation is close to or below the cap.
Pre-Money vs Post-Money SAFEs
The original SAFE was a pre-money instrument, meaning conversions were calculated based on pre-money valuation. In 2018, Y Combinator introduced the post-money SAFE, which has become the new standard. The key difference is how dilution is allocated. In a pre-money SAFE, additional SAFEs dilute both founders and existing SAFE holders. In a post-money SAFE, the cap represents a post-money valuation that includes all SAFE holders but excludes the new round's investors, giving each SAFE holder a predictable ownership percentage. This calculator uses a simplified pre-money model for clarity, but the concepts apply to both versions.
Most Favored Nation (MFN) Clauses
An MFN clause gives the SAFE holder the right to adopt the terms of any subsequent SAFE or convertible instrument the company issues, if those terms are more favorable. This is particularly common on SAFEs without a cap, where the investor wants protection against the company later offering a cap to another investor. MFN provisions ensure that early investors are not disadvantaged by later negotiations, and they incentivize founders to set fair terms from the beginning of their fundraise. If the MFN option is toggled on in this calculator, it serves as a reminder that the effective terms may change before conversion.
Common Pitfalls in SAFE Calculations
Founders frequently underestimate the dilution from outstanding SAFEs because the shares are not yet on the cap table. Stacking multiple SAFEs at different caps can lead to significant dilution surprises at the priced round. It is critical to model your cap table with all outstanding SAFEs included before negotiating Series A terms. Additionally, option pool increases negotiated during the priced round can further dilute founders, as the pool is typically carved out of the pre-money valuation. Always consult with a startup attorney and use detailed cap table management software alongside simplified calculators like this one.