What Is a SAFE Note? Valuation Caps, Discounts and Conversion Explained

An angel investor says they’re in for $100,000, and their lawyer sends a SAFE instead of a stock purchase agreement. It’s 6 pages long, there’s no price per share, and the only number that seems to matter is something called a “post-money valuation cap.” Should you sign it?

SAFEs have become one of the most common ways for early-stage startups to raise their first outside money, because they are fast, cheap to paper and postpone the hard question of what the company is worth. That convenience comes with tradeoffs that many founders only notice when the SAFEs convert and their ownership is smaller than they expected. This guide explains how SAFEs work, what each term does and how conversion plays out with real numbers.

This is general information, not legal, tax or investment advice. Work with a startup lawyer before signing or issuing a SAFE.

What a SAFE is

SAFE stands for simple agreement for future equity. Y Combinator created it in 2013 as a simpler alternative to convertible notes, and in 2018 moved its standard form to the post-money SAFE, which is the version most US startups use today. YC publishes the forms for free.

Under a SAFE, an investor pays the company now. In return, they get the right to receive shares later, typically preferred stock in the company’s next priced equity round. Until then, the investor doesn’t own shares, doesn’t vote and doesn’t get a board seat by default.

Key features:

• Not a loan. There is no interest rate, no repayment schedule and no maturity date.
• No price set today. The conversion price is worked out later using the cap, discount or both.
• Automatic conversion. Under YC’s post-money SAFE, the SAFE converts when the company sells preferred stock in an equity financing, with no minimum round size required.
• Standard form. Most investors accept the YC templates with few changes, which keeps legal costs down.

The SEC’s investor education office warns that despite the name, a SAFE may not be “simple” or “safe” for investors, because conversion may never happen if the company never raises a priced round.

SAFE vs convertible note vs priced round

Key takeaway: A SAFE delays pricing but doesn’t delay dilution. Every SAFE you sign is a promise of ownership that shows up all at once when you raise your priced round, so track it from day 1.

The terms that matter

For other startup and tech terms, see our glossary.

Valuation cap

The valuation cap is the maximum company valuation at which the SAFE converts. If your priced round comes in above the cap, the SAFE investor converts as if the company were worth only the cap, which rewards them for investing early.

With YC’s post-money SAFE, the cap is measured after all SAFE money is counted but before the new priced-round money. That makes the math simple: the investor’s ownership just before the priced round equals their investment divided by the cap. A $100,000 SAFE at a $5 million post-money cap buys roughly 2% of the company before the new round’s dilution.

Discount

A discount gives the SAFE investor a lower price than new investors pay in the priced round. A 20% discount means they convert at 80% of the round’s price per share. YC offers a discount-only form. Some SAFEs, especially older or custom ones, include both a cap and a discount and give the investor whichever produces the lower price.

Most favored nation (MFN)

An uncapped MFN SAFE has no cap or discount. Instead, if the company later issues SAFEs with better terms, this investor can adopt them. It is sometimes used for very early friends-and-family checks.

Pro rata rights

YC offers an optional pro rata side letter that lets an investor buy into the next round to maintain their ownership percentage. It is a separate document, so you can decide investor by investor.

How a SAFE converts: a worked example

Here is a simplified example. Real conversions depend on your exact documents and cap table, so your lawyer will run the final numbers.

The setup: - An angel invests $250,000 on a post-money SAFE with a $5 million valuation cap. - Later, the company raises a Series A at a $12 million pre-money valuation. - Just before the Series A, the company has 10 million fully diluted shares, including founders’ shares, the option pool and the shares the SAFE converts into.

Step 1: Find the Series A price. $12,000,000 ÷ 10,000,000 shares = $1.20 per share.

Step 2: Find the SAFE price. $5,000,000 cap ÷ 10,000,000 shares = $0.50 per share. Because $0.50 is lower than $1.20, the cap applies.

Step 3: Find the SAFE shares. $250,000 ÷ $0.50 = 500,000 shares, or 5% of the company just before the Series A.

Step 4: Apply the new round’s dilution. If Series A investors put in $3 million at $1.20 per share, they receive 2.5 million new shares. The company now has 12.5 million shares, and the SAFE holder owns 500,000 of them, or 4%.

What if it were a 20% discount instead? The SAFE price would be 80% of $1.20, or $0.96. The same $250,000 would buy only about 260,000 shares. When the round’s valuation is far above the cap, the cap is worth much more to the investor. When the round is priced close to or below the cap, the discount can matter more.

What if the company is sold first? Under YC’s post-money SAFE, if a sale happens before conversion, the investor generally receives the greater of their money back or the amount their shares would be worth if converted at the cap. If the company shuts down, SAFE holders are paid ahead of common stockholders from whatever is left, which is often nothing.

Common SAFE mistakes founders make

1. Losing track of stacked SAFEs. Raising several SAFEs at different caps feels painless, but they all convert at once. Founders can lose far more ownership than they planned.
2. Ignoring the option pool. Series A investors usually want a larger option pool created before their round, which dilutes existing holders, including founders and sometimes SAFE holders, depending on the terms.
3. Setting a cap too low out of urgency. A low cap can cost you meaningful ownership later. Compare caps with recent rounds at your stage and in your sector.
4. Editing the standard form without a lawyer. Small changes to definitions can change how conversion works.
5. Missing securities law steps. SAFEs are securities. Most are sold under exemptions such as Regulation D, which can involve filing a Form D with the SEC and notices in some states.
6. Skipping the pro forma model. Before signing, model what your cap table looks like after conversion at a few possible Series A valuations.

When a SAFE is the right tool

A SAFE tends to fit when:

• You’re raising a small pre-seed or seed amount from angels or accelerators
• You want to close investors one at a time as they commit
• It is too early to agree on a valuation
• Your investors are comfortable with standard YC terms
• You need a modest amount to build and test a first product, as covered in our MVP development guide

It is a weaker fit when you’re raising a large amount, when your business isn’t aiming for venture-style growth and may never raise a priced round, or when investors want governance rights now. For those, a priced round or other financing may be better. Local businesses that won’t raise venture money may be better served by SBA loans or grants.

Where to start

1. Read the YC SAFE forms and user guide. They are free and explain the mechanics with examples.
2. Build a simple cap table in a spreadsheet or cap table tool and add each SAFE as you sign it, with the amount, cap, discount and date.
3. Model 3 Series A scenarios, such as low, expected and high valuations, to see your ownership after conversion.
4. Pick one form and one set of terms for the round where possible, so the math stays clean.
5. Hire a startup lawyer to review the documents and handle any required securities filings.
6. Prepare your story. Investors still want a clear plan, so pair your SAFE round with a strong pitch deck.

The bottom line

A SAFE is a quick, low-cost way to take early investment without setting a valuation. The valuation cap and discount decide how much of your company the investor eventually gets, and the post-money SAFE makes that math easier to see. Track every SAFE you sign, model the conversion before you agree to a cap and get legal advice before you send the signature link.

Sources

• Y Combinator: SAFE financing documents — post-money SAFE forms, history and conversion mechanics
• Investor.gov: Be Cautious of SAFEs in Crowdfunding — SEC investor bulletin on SAFE risks
• SEC: Regulation Crowdfunding — rules for offering securities, including SAFEs, through crowdfunding