Ownership Percentage Calculator

What is Ownership Percentage? Ownership percentage is your share of a company’s equity, expressed as a percent of the total share count. On a fully diluted basis, it reflects yo...

Ownership Percentage Calculator

Compute your equity ownership as a percentage of fully diluted shares, with simple inputs, helpful tooltips, scenarios, and a concise What It Means panel.

shares

Total fully diluted shares outstanding, including issued shares plus in-the-money options and other convertible instruments. Ownership is measured against this number.

shares

Number of shares (or share equivalents) you hold on a fully diluted basis. This includes vested options or units that are economically equivalent to common shares.

Scenarios
Quickly see how your stake changes as your shares or the total fully diluted share count changes.
Employee with a small option grantFounder with significant minority stakeAngel investor minority stakeControlling shareholder

Results

  • Your ownership percentage— %
  • Stake profile—

Enter your inputs above to calculate the results.

What is Ownership Percentage?

Ownership percentage is your share of a company’s equity, expressed as a percent of the total share count.

On a fully diluted basis, it reflects your economic stake after accounting for all securities that could convert into shares—critical for fundraising, option pool planning, equity dilution, governance, and exit value allocation.

Formula

Ownership Percentage = Your Shares / Total Fully Diluted Shares × 100

Example

Total fully diluted shares: 10,000,000

Your shares: 1,500,000

Ownership Percentage = 1,500,000 / 10,000,000 × 100 = 15%

Interpretation: 15% fully diluted ownership (often viewed as a significant minority stake, depending on governance terms and protective provisions).

Frequently Asked Questions

What should I use for “total fully diluted shares” (and why not just outstanding shares)?

Use the fully diluted share count from your latest cap table: outstanding shares plus shares that could be created from options, warrants, and other convertibles. This is the ownership percentage most investors and finance teams rely on.

I only know my ownership % (not my share count). Can I still use this calculator?

Not directly—this tool needs your shares. Pull your share count from your equity grant/stock certificate and your fully diluted total from the cap table. If you only have %, ask whoever maintains the cap table for the underlying numbers.

Why does my ownership % differ from what my cap table shows?

Common reasons: you’re comparing undiluted vs fully diluted, the cap table includes an unallocated option pool, you’re using an older share count, or you’re mixing share classes/conversion assumptions.

How do I model dilution from a new funding round or option pool increase?

This calculator answers “what % do I own today?” To model “what happens after new shares are issued,” use an Equity Dilution / Post-round Ownership calculator where you add the new shares (and any option pool refresh) to the denominator.

Sources & Methodology