The Series A Ownership Calculator estimates post-financing ownership from a pre-money valuation and a new cash investment. It separates the new investor’s percentage from the percentage retained by existing shareholders and displays the resulting post-money valuation.
This is useful when a term sheet states a valuation and investment amount but does not immediately show the ownership split. The model assumes one priced equity round with no option-pool adjustment, convertible conversion, warrants, or transaction costs.
1. Enter the pre-money valuation
Use the value assigned to the company before the Series A cash is invested.
2. Enter the new investment
Include only the new priced-equity cash modeled in this calculation.
3. Read investor ownership
The main result shows the investor’s share of the post-money company.
4. Compare retained ownership
The details show the percentage that remains with existing shareholders and the implied post-money valuation.
Post-money valuation = Pre-money valuation + New investment. Investor ownership = New investment ÷ Post-money valuation × 100.
The result is the percentage of the company owned by the new investor immediately after the financing under the stated valuation assumptions.
Fully diluted ownership may differ after accounting for employee options, convertibles, warrants, or other securities.
Given: Pre-money valuation = $12,000,000; new investment = $3,000,000.
Calculation: Post-money valuation = $12,000,000 + $3,000,000 = $15,000,000. Investor ownership = $3,000,000 ÷ $15,000,000 = 20%.
Result: The new investor owns 20%, while existing holders retain 80%.
No. Ownership after the round is based on post-money valuation, which includes the new investment.
It represents all pre-round holders as one group. A detailed cap table is needed to split that percentage among founders, employees, and earlier investors.
A pre-money option-pool increase usually dilutes existing holders before the new investment. That effect is not included in this simplified calculation.
Yes. With no new investment, investor ownership is 0% and existing holders retain 100%.
Investor ownership is the new investor’s post-round percentage. In this simple model, that same percentage is the reduction applied proportionally to existing holders.