How SAFEs Affect Your Cap Table: Understanding Conversion and Dilution

SAFE can be an efficient way to raise capital without negotiating a priced equity round. But while the financing may be simpler to execute, its effect on your ownership can be less straightforward. Unlike a priced round, a SAFE doesn't immediately issue shares to the investor. Instead, it gives the investor the right to receive equity when a specified event occurs, typically a future priced financing.

The important question for founders is not just how much money they're raising. It's how much of the company that money will ultimately represent — and who will absorb the dilution.

That answer depends on the terms of the SAFE, particularly whether it uses a pre-money or post-money valuation cap.

This article explains how SAFE conversion works, walks through the calculations, and compares the ownership outcomes under different SAFE structures.

What Is a SAFE?

SAFE stands for Simple Agreement for Future Equity. Developed by Y Combinator in 2013, it allows a company to receive investment capital in exchange for contractual rights to future equity.

A SAFE differs from a traditional equity investment because the investor generally does not receive shares at signing. Instead, the SAFE converts into equity upon a qualifying financing or another event specified in the agreement.

A SAFE also differs from a convertible promissory note. Standard SAFEs are not debt, do not accrue interest, and do not have a maturity date.

A company's cap table should track outstanding SAFEs even though they have not yet converted into issued shares. Otherwise, founders risk underestimating the dilution associated with their next financing.

Understanding the Key SAFE Terms

Before calculating conversion, it's important to understand several terms commonly found in SAFE agreements:

Investment amount: The capital contributed by the SAFE investor.

Valuation cap: A contractual valuation threshold used to calculate the investor's conversion price. A cap generally rewards early investors by allowing conversion at a more favorable price if the company's valuation increases before the next financing.

Discount rate: A provision allowing a SAFE investor to convert at a specified discount to the price paid by new investors in a priced round. For example, a 20% discount generally means conversion at 80% of the new investor's price per share.

Conversion price: The price per share used to determine how many shares the SAFE investor receives when the instrument converts.

Equity financing: A priced investment round that triggers conversion under the terms of the SAFE.

Company capitalization: The share count defined in the SAFE for purposes of determining the conversion price. Importantly, the definition varies between pre-money and post-money SAFEs.

SAFEs may have a valuation cap, a discount, or other conversion provisions. Not every SAFE contains both a cap and a discount, and the conversion calculation must follow the actual agreement.

Pre-Money vs. Post-Money SAFEs: What's the Difference?

The distinction between pre-money and post-money SAFEs is one of the most important considerations for founders. Y Combinator originally introduced a pre-money SAFE in 2013 and adopted a post-money version in 2018 to make the ownership consequences of SAFE financing more transparent. Both structures allow investors to provide capital before a priced equity round, but they allocate dilution differently.

Pre-Money SAFE

A pre-money SAFE uses a valuation cap measured before the SAFE financing proceeds are included. The investor's ultimate ownership depends on the capitalization at conversion, including the treatment of other convertible securities and potentially an option pool increase.

As a result, the exact ownership percentage generally cannot be determined solely from the investment amount and valuation cap when the SAFE is signed. When multiple pre-money SAFEs are issued, they can dilute one another upon conversion.

Post-Money SAFE

A post-money SAFE uses a valuation cap that incorporates SAFE financing proceeds.

Under a standard post-money valuation-cap SAFE, assuming the valuation cap governs conversion, the ownership percentage sold can generally be calculated as:

Investment amount ÷ Post-money valuation cap = SAFE ownership

For example:

$500,000 ÷ $5,000,000 = 10%

This means the SAFE investor is entitled to approximately 10% of the company's capitalization immediately before the new priced-round investment, subject to the agreement's specific conversion mechanics. Crucially, that 10% is measured after accounting for the SAFE financing but before the new money invested in the priced round.

Additional post-money SAFEs generally dilute the existing shareholders rather than earlier post-money SAFE investors. That's an important difference, particularly for founders who raise capital through multiple SAFEs over time.

A Worked Example: How SAFE Conversion Changes Ownership

Consider a startup with 10 million outstanding founder shares.

The company raises $1 million through two SAFEs:

• Investor A contributes $500,000.

• Investor B contributes $500,000.

• Both SAFEs have a $5 million valuation cap.

Later, the company raises $2 million in a priced equity round at an $8 million pre-money valuation.

We'll compare what happens when the two SAFEs use pre-money versus post-money valuation caps.

To isolate the effects of the SAFE structures, assume there are no outstanding options, option pool increases, warrants, convertible notes, or other securities. Both SAFEs convert at their valuation caps, and the priced round's $8 million pre-money valuation applies to the capitalization immediately before the new investment.

Scenario 1: Two Pre-Money SAFEs

Start with the company's 10 million outstanding shares. Each SAFE investor contributed $500,000 at a $5 million pre-money valuation cap.

Step 1: Calculate the SAFE conversion price.

Under the simplified legacy pre-money SAFE structure, the conversion price is:

$5,000,000 ÷ 10,000,000 = $0.50 per share

Step 2: Calculate the shares issued to each SAFE investor.

$500,000 ÷ $0.50 = 1,000,000 shares

Both SAFE investors receive 1 million shares.

Step 3: Calculate the capitalization after SAFE conversion.

10,000,000 founder shares + 2,000,000 SAFE shares = 12,000,000 shares

The resulting ownership is:

Holder	Shares	Ownership
Founders	10,000,000	83.33%
SAFE Investor A	1,000,000	8.33%
SAFE Investor B	1,000,000	8.33%
Total	12,000,000	100%

Notice that each SAFE investor receives approximately 8.33%, even though a simple calculation of $500,000 divided by $5 million would suggest 10%. That's because the two pre-money SAFEs dilute each other.

Scenario 2: Two Post-Money SAFEs

Now consider the same investments using standard post-money valuation-cap SAFEs.

Step 1: Calculate the ownership sold to each SAFE investor.

$500,000 ÷ $5,000,000 = 10%

Each investor receives 10% of the company immediately before the priced-round investment, assuming cap-based conversion.

Step 2: Calculate the founders' remaining ownership.

100% − 10% − 10% = 80%

Step 3: Calculate the total capitalization after SAFE conversion.

Because the founders' 10 million shares represent 80% of the capitalization:

10,000,000 ÷ 0.80 = 12,500,000 shares

Step 4: Calculate the shares issued to each SAFE investor.

12,500,000 × 10% = 1,250,000 shares

The resulting ownership is:

Holder	Shares	Ownership
Founders	10,000,000	80.00%
SAFE Investor A	1,250,000	10.00%
SAFE Investor B	1,250,000	10.00%
Total	12,500,000	100%

The investors receive more shares under the post-money SAFE structure because their ownership percentages are calculated after accounting for both SAFE investments.

The difference is meaningful: the founders retain 80% under the post-money SAFEs, compared with approximately 83.33% under the pre-money SAFEs. These are different economic terms, even though the dollar amounts of their valuation caps are identical.

What Happens When the Priced Round Closes?

Now assume the company completes its $2 million financing at an $8 million pre-money valuation, without an additional option pool increase.

The post-money valuation is:

$8,000,000 + $2,000,000 = $10,000,000

The new investor receives:

$2,000,000 ÷ $10,000,000 = 20%

The existing shareholders, including the converted SAFE investors, collectively retain 80% of the company.

We can now compare the final ownership percentages.

Holder	Pre-money SAFEs	Post-money SAFEs
Founders	66.67%	64.00%
SAFE Investor A	6.67%	8.00%
SAFE Investor B	6.67%	8.00%
New priced-round investor	20.00%	20.00%
Total	100%	100%

Percentages are rounded. Both scenarios assume cap-based SAFE conversion and no additional dilutive events.

In the pre-money SAFE scenario, the founders retain approximately 66.67% after the priced round. In the post-money SAFE scenario, they retain 64%.

The company's financing proceeds are identical: $1 million from the SAFEs and $2 million from the priced round. Yet the founders end up with different ownership percentages because the SAFE structures determine how dilution is allocated.

The lesson: The investment amount and stated valuation cap do not tell you everything you need to know about the equity you're selling. The SAFE structure matters.

What If You Raise Capital Through Multiple SAFEs?

One of the benefits of post-money SAFEs is that founders can calculate the approximate ownership they're selling as they raise money. But that transparency doesn't eliminate dilution.

Consider a company that signs three post-money valuation-cap SAFEs:

SAFE	Investment	Post-money cap	Ownership sold
Investor A	$250,000	$5,000,000	5%
Investor B	$500,000	$8,000,000	6.25%
Investor C	$750,000	$10,000,000	7.5%
Total	$1,500,000		18.75%

Before any subsequent priced round, the company has sold 18.75% of its capitalization through these SAFEs, assuming each converts at its cap under the standard post-money structure. The existing shareholders collectively retain 81.25%.

If a subsequent priced round sells another 20% of the company, without other dilutive events, the existing shareholders' ownership falls to:

81.25% × 80% = 65%

The founders and other existing holders have now experienced 35 percentage points of dilution relative to their original collective 100% ownership, across the SAFE financings and the priced round. This illustrates why founders should track the cumulative effect of every SAFE, rather than evaluating each investment in isolation.

Founder Insight

Track cumulative SAFE dilution, not just individual investments. A series of modest SAFE financings can represent a substantial percentage of your company. Maintain a running capitalization model that shows the combined impact of all outstanding SAFEs, potential option pool increases, and the next priced financing.

How Do Valuation Caps and Discounts Affect Conversion?

So far, our examples have assumed that the valuation cap determines the SAFE conversion price.

But that isn't always the case.

A SAFE investor may receive a conversion discount instead of, or in certain agreements in addition to, a valuation cap.

Consider a priced round in which new investors pay $1.00 per share. If an earlier investor holds a SAFE with a 20% discount, the discounted conversion price would generally be:

$1.00 × 80% = $0.80 per share

A $200,000 investment converting at $0.80 per share would receive:

$200,000 ÷ $0.80 = 250,000 shares

If an applicable valuation cap produces a lower conversion price, the agreement may provide for conversion at that lower price instead. However, the calculation must follow the specific SAFE's terms, including how its capitalization and conversion alternatives are defined. The practical implication is that founders should model the conversion price of each SAFE rather than assuming all convertible investments will convert on identical terms.

How Does an Option Pool Increase Affect SAFE Holders?

Option pools introduce another important consideration.

As discussed in our article Cap Table Fundamentals: What Founders Should Know Before They Raise, investors may require companies to expand their employee option pools as part of a priced financing.

Under the standard Y Combinator post-money SAFE, the existing option pool is generally included in the SAFE capitalization calculation. However, a new or increased option pool established in connection with the priced round is generally excluded from that calculation.

As a result, the additional pool shares typically dilute both the existing shareholders and the SAFE investors, while the new priced-round investor's negotiated ownership is maintained.

Legacy pre-money SAFEs can allocate this dilution differently because their capitalization definitions and conversion mechanics differ.

This is another reason to model the full financing transaction, including SAFE conversion, option pool expansion, and the issuance of new investor shares, before signing a term sheet.

Common SAFE Modeling Mistakes to Avoid

1. Treating the valuation cap as the company's current valuation. A SAFE valuation cap is a contractual conversion mechanism, not necessarily a determination of the company's fair market value.

2. Assuming pre-money and post-money caps are interchangeable. The same investment amount and numerical cap can produce different ownership outcomes under the two structures.

3. Evaluating SAFEs individually rather than cumulatively. Multiple SAFE investments can represent a substantial percentage of the company's eventual capitalization.

4. Ignoring the possibility of an unfavorable conversion scenario. When a priced round occurs at a valuation at or below the SAFE's cap, conversion may not produce the ownership percentage initially estimated from the cap alone.

5. Overlooking option pool requirements. The size and timing of an option pool increase can materially change the ownership of founders and SAFE holders.

6. Failing to model the next financing. The ownership a SAFE represents immediately before a priced round is not necessarily the percentage the investor retains after the new capital is invested.

What Founders Should Calculate Before Signing a SAFE

Before accepting a SAFE investment, founders should understand its potential effect on the company's capitalization. At a minimum, that means calculating the ownership implied by the investment and valuation cap, accounting for all previously issued SAFEs and other convertible securities, and projecting the ownership structure after a future priced round.

It's also worth evaluating how the results change under different financing valuations, conversion provisions, and option pool assumptions. A complete capitalization model should distinguish between current outstanding ownership, ownership after SAFE conversion, and ownership after the next financing. These are different measurements, and each answers a different question.

Understanding Dilution Before It Happens

SAFEs can make early fundraising more efficient by postponing some of the negotiations associated with a priced equity round. But they don't eliminate the economic consequences of issuing equity.

The distinction between pre-money and post-money SAFEs determines how ownership is calculated and how dilution is allocated. Multiple SAFEs, conversion terms, option pool requirements, and subsequent financing rounds can all affect the ultimate result.

For founders, the objective isn't necessarily to minimize dilution at every stage. It's to understand the ownership being exchanged for capital and evaluate whether that tradeoff supports the company's growth.

At Promptly, we believe informed fundraising starts with understanding the financial mechanics behind each investment. The more clearly founders understand how their financing instruments affect the cap table, the better equipped they are to evaluate terms and plan for future capital needs.

For an introduction to capitalization tables, priced rounds, and option pool dilution, read Cap Table Fundamentals: What Founders Should Know Before They Raise.