Y Combinator SAFE Agreement: Templates, Terms, and How to Use Them

If you're raising a pre-seed or seed round, there's a near-universal starting point: the Y Combinator SAFE. Since YC introduced it in 2013, the Simple Agreement for Future Equity has become the default instrument for early-stage fundraising — used by thousands of startups and accepted by nearly every institutional seed investor in the United States. But "simple" doesn't mean consequence-free. The terms you accept today will shape your cap table for years.

This guide breaks down everything founders and investors need to know about the YC SAFE: where to get the templates, how the key terms work, and when a priced round might be the better choice.

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What Is the Y Combinator SAFE?

The YC SAFE is a standardized convertible security that gives investors the right to receive equity in a future priced round, in exchange for capital today. It's not debt — there's no interest rate, no maturity date, and no obligation to repay. The investor is simply betting that a priced round will happen and that the company will be worth more by the time it does.

YC published the original SAFE in late 2013 as a cleaner alternative to convertible notes. In 2018, it released a significantly updated version — the "post-money SAFE" — which changed the economic math in ways that matter enormously to founders.

The post-money SAFE is now the default. If someone hands you a "YC SAFE template" without specifying which version, confirm which one you're looking at before signing anything.

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Where to Find the Official YC SAFE Templates

YC publishes all four SAFE variants for free at ycombinator.com/documents. No login required. The four versions are:

• Post-Money SAFE — Valuation Cap, No Discount
• Post-Money SAFE — Discount, No Valuation Cap
• Post-Money SAFE — MFN (Most Favored Nation), No Valuation Cap, No Discount
• Post-Money SAFE — Valuation Cap and Discount

Each template is available as a Word document and a PDF. YC also provides a term sheet template and an explanation document that founders should read before using the forms.

For most early-stage raises, the valuation cap, no discount version is the most commonly used. The MFN variant is typically reserved for very early checks written before a founder has established enough traction to justify a cap.

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Key Terms in a YC SAFE Agreement

Valuation Cap

The valuation cap sets the maximum company valuation at which an investor's SAFE converts into equity. If you raise at a $10M cap and the Series A prices at a $30M pre-money valuation, the SAFE investor converts as if the company were worth $10M — receiving three times more equity per dollar than new Series A investors.

The cap protects early investors from being diluted into irrelevance when a company raises at a much higher valuation later. From a founder's perspective, it defines the floor for how much equity you're implicitly giving away at the time of signing.

What's a reasonable cap? It depends entirely on stage and market. In 2023–2024, pre-seed caps for software companies typically ranged from $8M to $20M, with competitive AI and infrastructure deals occasionally pushing above $25M. YC companies raising on SAFEs during the batch often use caps between $15M and $25M given YC's brand premium.

Discount Rate

A discount gives the SAFE investor the right to convert at a reduced price relative to new investors in the next priced round. A 20% discount means if Series A investors pay $1.00 per share, the SAFE investor pays $0.80.

Most SAFEs use either a cap or a discount — not both. When both are present, the investor typically receives whichever results in more equity (lower effective price). Investors occasionally push for both terms; founders should understand that stacking these significantly increases dilution.

Post-Money vs. Pre-Money SAFE: Why It Matters

This is the detail that trips up the most founders.

The pre-money SAFE (the 2013 version) calculated the investor's ownership before accounting for the SAFE pool itself. The result: as more SAFEs were issued, each SAFE investor's ownership percentage at conversion was diluted by the other SAFEs — but founders often didn't realize this until it was too late.

The post-money SAFE (2018 version) locks in each investor's ownership percentage at the time of signing, including the dilution from the SAFE itself. The formula is:

> Ownership % = Investment Amount ÷ Post-Money Valuation Cap

This sounds cleaner — and it is more transparent — but the economic impact shifts. Each post-money SAFE investor now has a fixed ownership claim, and the dilution from stacking multiple SAFEs falls almost entirely on the founders, not on each other.

Example: If you raise $2M total across four SAFEs at a $10M post-money cap, you've already given away 20% of your company before a single priced round closes. Model this carefully before you commit.

Pro-Rata Rights

Most YC SAFEs include optional pro-rata rights, giving investors the right to participate in the next priced round to maintain their ownership percentage. Institutional investors almost always want this. For founders, pro-rata obligations can complicate future rounds by creating a long list of small investors with rights that new lead investors find inconvenient.

It's common to negotiate pro-rata rights only for investors above a certain check size (e.g., $500K+) or to exclude them entirely for angel checks.

Most Favored Nation (MFN) Clause

The MFN clause is included in the no-cap, no-discount SAFE variant. It entitles the investor to the benefit of any better terms offered to future SAFE investors. If you later issue a SAFE with a $10M cap, your MFN investor can elect to also receive a $10M cap.

MFN SAFEs are useful for very early checks where a company hasn't established a clear value, but they create administrative complexity and investor management overhead. Use them sparingly.

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How SAFE Conversion Works in Practice

SAFEs convert into equity at a "qualified financing" — typically defined as an equity round raising a minimum threshold (often $1M or more, though this is negotiable). At conversion:

1. The company and new lead investor agree on a pre-money valuation for the priced round
2. SAFE investors convert at the lower of their cap or the new round price (if a discount applies, that's factored in too)
3. The conversion creates new shares, diluting all existing shareholders — but the SAFE investors receive their contractually defined ownership
4. The SAFE is extinguished

If the company is acquired before a priced round, most YC SAFEs include a liquidity event provision. Investors can choose between receiving their pro-rata share of acquisition proceeds or converting at the cap. This is an important protection in acqui-hire scenarios where a traditional equity holder might receive little or nothing.

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Priced Round vs. SAFE: When to Use Each

The SAFE is not always the right instrument. Understanding the tradeoffs helps both founders and investors make better decisions.

When a SAFE Makes Sense

• Speed: A SAFE can close in days. A priced round requires legal counsel, a term sheet, investor rights agreements, board seat negotiations, and often 60–90 days of work.
• Cost: SAFE legal fees can be as low as $1,500–$5,000. A priced round typically costs $20,000–$50,000 or more in legal fees for both sides.
• Early-stage uncertainty: When valuation is genuinely hard to establish — pre-product, pre-revenue — deferring the pricing conversation is often sensible for both parties.
• Rolling closes: SAFEs allow founders to close individual checks as investors commit, rather than holding all capital until a single closing date.

When a Priced Round Makes Sense

• Investor preference: Some institutional LPs require their fund managers to invest in priced rounds for portfolio accounting purposes. Certain family offices and corporate VCs will not sign SAFEs.
• Larger raise sizes: Once you're raising $5M or more, the legal cost of a priced round becomes proportionally small, and the investor protections a priced round provides become more important.
• Board governance: If investors are writing large checks, they typically want a board seat and formal protective provisions — neither of which a SAFE provides.
• Clarity on ownership: A priced round creates a formal cap table with defined ownership. SAFE investors often don't appear on the cap table until conversion, which can cause confusion in due diligence for subsequent rounds.

Key Differences at a Glance

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Common Mistakes Founders Make With SAFEs

Issuing too many SAFEs without modeling dilution. Because SAFEs feel "lightweight," founders sometimes stack them carelessly. Run a dilution model before every new SAFE issuance. Tools like Carta and Pulley make this straightforward.

Using the wrong template version. Pre-money and post-money SAFEs have materially different economics. Default to the post-money version unless you have a specific reason to use the older form.

Not reading the conversion mechanics. The qualified financing threshold, the treatment of a liquidity event, and the definition of "capital stock" all have meaningful consequences. Read the full agreement, not just the term sheet summary.

Forgetting pro-rata rights add up. If twenty angel investors each have pro-rata rights into your Series A, your lead investor may balk. Consider limiting or excluding pro-rata rights in early small-check SAFEs.

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Actionable Takeaways

• Download the official templates directly from ycombinator.com/documents — never use a third-party copy without verifying it against the current YC version.
• Use the post-money SAFE with a valuation cap as your default instrument for pre-seed fundraising.
• Before signing any SAFE, calculate the implied ownership: Investment ÷ Post-Money Cap = Ownership %. Know exactly what you're giving away.
• Model total dilution across all SAFEs before issuing new ones. Assume your SAFE investors will all convert at cap, and stress-test your cap table at multiple Series A valuations.
• Consider a priced round once your raise exceeds $3M–$5M or when institutional investors make up the majority of your round.
• Get a startup-specialized attorney to review your documents even if the template is "standard." The terms are standard; your situation isn't.

The YC SAFE is one of the most founder-friendly innovations in venture finance history. Used correctly, it's a powerful tool. Used carelessly, it's a cap table disaster waiting to happen at Series A due diligence.