Free ForeverNo SignupCap TableUpdated 2026

Investor Ownership Calculator

Calculate exactly what percentage of the company new investors own after a round — and what it means for your cap table.

Investor ownership % = Investment ÷ Post-Money Valuation. Simple to calculate but the details matter: option pools created pre-money dilute founders, not investors. Pro-rata rights mean existing investors may invest again. Always model the full cap table, not just the new investors.

Total Investment Amount

Total cash raised from all investors this round

Pre-Money Valuation

Agreed company valuation before this investment

New Option Pool (Pre-Money)Optional — accounts for option pool shuffle

Employee equity pool added before investment (dilutes founders)

Founder Ownership (Pre-Round)Optional — calculates founder stake post-round

Total founder ownership before this round

The Formula

Investor % = Investment ÷ (Pre-Money + Investment) × 100

In plain English

Investor ownership = investment divided by post-money valuation (pre-money + investment).

Worked Example

$3M investment, $10M pre-money. Post-money = $13M. Investor % = $3M ÷ $13M = 23.1%.

Pro-Rata Rights and Their Impact

Pro-rata rights give existing investors the right to invest in future rounds to maintain their ownership percentage. If a seed investor owns 15% and the Series A would dilute them to 9%, pro-rata rights let them invest additional capital to stay at 15%.

Pro-rata rights are valuable to investors but create complexity for founders — you may be obligated to carve out investment room for existing investors in every future round. Negotiate whether pro-rata rights are major or minor (different thresholds for exercise).

Investor Ownership by Stage (2026)

Round	Typical Investor %	Pre-Money Range	Board Seats
Pre-seed	10–20%	$1M–$5M	Observer only
Seed	15–25%	$5M–$20M	1 board seat
Series A	20–30%	$15M–$60M	2 board seats
Series B	15–25%	$50M–$200M	2–3 board seats

Source: Carta State of Private Markets 2025 · Pitchbook Benchmark Report

Common Mistakes

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Calculating ownership before option pool creation

When the option pool is created pre-money, founders are diluted before investors come in. A "15% option pool pre-money" on a $10M pre-money deal means founders give up ~15% of the $10M before the investor's 23% is calculated.

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Confusing pre-money and post-money ownership

Post-money ownership is always lower than pre-money ownership for existing shareholders. New investors own investment/post-money, not investment/pre-money.

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Not accounting for future pro-rata exercises

Model all investors exercising their full pro-rata rights in every future round. If you have 8 investors with pro-rata, a Series B may have very limited new investor room available.