Free ForeverNo SignupFounder OwnershipUpdated 2026

Equity Dilution Calculator

See exactly how a new funding round dilutes your ownership — and what your stake is worth post-close.

Dilution = the reduction in your ownership percentage when new shares are issued. If you own 70% of 1M shares and issue 500K new shares, your ownership drops to 46.7% — even though you still own the same 700K shares. Dilution itself isn't bad; it's good if the new capital increases total value faster than it reduces your percentage.

Your Current Ownership

Your current percentage of the company

Pre-Money Valuation

Agreed company valuation before the new investment

Investment Amount

Total cash raised in this round

Option Pool IncreaseOptional — adds option pool dilution

New employee equity pool added pre-money (dilutes founders)

The Formula

New Ownership % = Current % × Pre-Money ÷ (Pre-Money + Investment)

In plain English

Post-money = pre-money + investment. New ownership = current % × (pre-money / post-money).

Worked Example

60% ownership, $5M pre-money, $2M raise. Post-money = $7M. New ownership = 60% × ($5M ÷ $7M) = 42.9%. Dilution = 17.1 percentage points.

Understanding Dilution in Startup Fundraising

Dilution is not inherently bad. The question is whether the capital raised creates enough value to justify the reduced ownership percentage. Owning 40% of a $50M company is worth far more than owning 70% of a $10M company.

The critical factor is the pre-money valuation. A high pre-money means less dilution for the same raise amount. This is why founders spend so much time on valuation negotiations — each percentage point of pre-money increase translates directly into retained founder ownership.

15–25%

Typical dilution per round

3–4×

Typical funding rounds before exit

20–30%

Founder ownership at Series B (average)

10%

Standard option pool pre-Series A

Typical Dilution by Round (2026)

Round	Raise	Dilution	Pre-Money Range
Pre-seed	$100K–$500K	10–20%	$500K–$3M
Seed	$500K–$3M	15–25%	$3M–$15M
Series A	$3M–$15M	15–25%	$10M–$50M
Series B	$15M–$50M	15–20%	$50M–$200M

Source: Carta State of Private Markets 2025 · AngelList Data Report 2024

Common Mistakes

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Forgetting the option pool shuffle

Investors often require you to create or expand an option pool pre-money — meaning it dilutes founders, not investors. A 10% post-money option pool requirement that's placed pre-money actually dilutes your effective pre-money valuation significantly.

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Focusing on percentage instead of dollar value

Founders fixate on ownership percentage but should focus on total dollar value of their stake. 35% of a well-funded, fast-growing company is worth more than 60% of an underfunded one.

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Not modelling future rounds

A single round's dilution seems manageable. Model three rounds forward: if each round dilutes 20%, after three rounds you're at 51% of your original ownership. Starting at 60% leaves you with ~31% at exit.