Stock Dilution Calculator
Estimate how new share issuance changes ownership percentage, implied post-money valuation, and EPS for existing shareholders.
Last updated: 2026-03-25
Stock dilution calculator
Enter your values
See how new equity issuance changes an existing shareholder's ownership percentage and simple EPS.
Post-Issuance Ownership
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Enter the current cap-table assumptions to estimate ownership dilution and EPS impact.
Calculation History(0)
Example calculations
Tap an example to prefill the calculator with sample values.
Direct issuance
10M shares outstanding, 1.5M new shares issued
A simple dilution check when management already knows the new-share count.
Result: Ownership drops from 8.0% to about 6.96%, with EPS spread across a larger share base
Funding round
$6M raise on a $40M pre-money
Useful when you know the valuation and check size but not the exact share count yet.
Result: The implied share issuance leads to roughly 13% dilution versus the pre-round ownership stake
How the dilution estimate works
The calculator starts with the current share count and your owned shares, then either adds a direct new-share issuance or derives the implied new shares from a round size and pre-money valuation.
It then recalculates ownership and a simple EPS figure using the same annual net income before and after the issuance. That isolates the dilution effect instead of hiding it behind growth assumptions.
Stock dilution FAQs
Ownership percentage, post-money value, and why EPS often weakens after issuance.
What does dilution mean here?
Dilution means your percentage ownership falls because the total share count rises while your personal share count stays the same.
Why show EPS impact too?
Because the ownership change is only part of the story. If net income does not rise along with the new share count, earnings per share get spread thinner across the cap table.
What is the difference between pre-money and post-money valuation?
Pre-money is the company value before the new capital arrives. Post-money is the pre-money value plus the new money raised in the round.
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</script> Related tools
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