Free Calculator

Dilution & Fundraising Simulator

Model how your ownership changes across SAFE, Seed, Series A, and Series B rounds. See the compounding effect of dilution and option pool shuffles on every stakeholder.

Founders:

Total: 100%

SAFE Note

SAFE Amount

Valuation Cap

Discount(20%)

0%50%

Seed Round

Amount Raised

Pre-Money Valuation

Option Pool(10%)

0%25%

Series A

Amount Raised

Pre-Money Valuation

Option Pool Top-Up(5%)

0%15%

Series B

Final Founder Ownership

49.4%

combined

Total Dilution

50.6%

Effective Price per %

$247K

capital raised per % diluted

Ownership Across Rounds

Stakeholder Value by Round

Stakeholder	Founding	Seed	Series A
Founder 1	50%	32.9% $3.3M	24.7% $12.4M
Founder 2	50%	32.9% $3.3M	24.7% $12.4M
SAFE Investors	--	5.88% $588K	4.41% $2.2M
Option Pool	--	9.41% $941K	12.1% $6.0M
Seed Investors	--	18.8% $1.9M	14.1% $7.1M
Series A Investors	--	--	20% $10.0M

Round Details

Typical dilution range. Most startups reaching Series B see founders diluted to 20-40%. Your 49.4% is within the normal range. Focus on growing the pie, not the slice.

Results are encoded in the URL - anyone with the link sees your model

How the dilution simulator works

This free dilution calculator models how founder ownership changes across a SAFE round, Seed, Series A, and Series B - including option pool shuffles, the mechanic most founders underestimate. Enter your founding split and round assumptions to see exactly what each founder would own at every stage. No signup required.

The formulas

Round dilution % = new shares issued / total shares after the round

Every new share issued to investors or the option pool reduces existing holders proportionally.

Ownership after = ownership before x (1 - round dilution %)

Dilution compounds: 20% dilution at seed followed by 20% at Series A leaves you with 64% of your original stake, not 60%.

Benchmarks founders should know

Typical seed round dilution: 15-25% - 20% is the common midpoint
Typical Series A dilution: 15-25%
Typical option pool: 10-15% - usually created pre-money, which dilutes founders rather than the new investors
Combined founder ownership after Series A: commonly 50-65%

Frequently asked questions

What is equity dilution?

Dilution is the reduction in your ownership percentage when a company issues new shares - to investors in a funding round, or to employees through an option pool. Your share count stays the same, but the total grows.

How much equity do founders give up in a seed round?

Typically 15-25%, with 20% a common midpoint. Add an option pool of around 10% created pre-money, and effective founder dilution in a seed round often reaches 25-30%.

What is an option pool shuffle?

Investors usually require the employee option pool to be created before their money comes in ("pre-money"), so the pool dilutes only the existing holders - the founders - rather than the new investors. This simulator models that explicitly.

How does a SAFE convert?

A SAFE converts to equity at the next priced round, at the better of its valuation cap or discount for the investor. Until conversion the dilution is invisible on your cap table - this simulator shows the conversion impact explicitly.

Is this dilution calculator free?

Yes. The Accelerator.tools dilution simulator is completely free, requires no signup, and scenarios can be shared via URL.

Last updated July 2026 by the Accelerator.tools editorial team. Explore more free tools in the calculator library or browse the community-voted tool directory.