The Series A Funding Calculator estimates the amount of new capital associated with a target investor ownership percentage and a stated pre-money valuation. It also shows the implied post-money valuation, the dollar value of existing shareholders after the round, and the percentage dilution created by the financing.
Founders, finance leads, and investors can use the result to check whether a proposed raise and ownership target are internally consistent before building a detailed capitalization table. The calculator uses a simple priced-equity model and does not model option-pool top-ups, convertible instruments, transaction fees, or multiple security classes.
1. Enter the pre-money valuation
Use the negotiated company value immediately before the new investment.
2. Set the target investor ownership
Enter the percentage the new Series A investor is expected to own after closing.
3. Review the funding estimate
The main result shows the investment amount implied by those two assumptions.
4. Check valuation and dilution
Use the detail rows to review post-money value and the percentage retained by existing holders.
Funding = Pre-money valuation × Investor ownership ÷ (1 − Investor ownership). Post-money valuation = Pre-money valuation + Funding.
The main result is the new cash investment required for the investor to own the selected percentage immediately after the round under a simple priced-equity structure.
Actual financing documents may produce different ownership because of option pools, convertibles, warrants, fees, or different share classes.
Given: Pre-money valuation = $12,000,000; target investor ownership = 20%.
Calculation: Funding = $12,000,000 × 0.20 ÷ (1 − 0.20) = $3,000,000. Post-money valuation = $15,000,000.
Result: The implied Series A raise is $3,000,000. Existing holders retain 80% of the company.
Investor ownership is measured after the new cash is added. Dividing by one minus the ownership rate converts the pre-money value into the required post-money investment.
Only if the pool increase is already reflected in the pre-money valuation and ownership assumption. A separate pool top-up can create additional founder dilution.
Not directly. Those instruments require conversion terms, caps, discounts, and possibly accrued interest before ownership can be calculated.
A 100% target would make the formula undefined because no ownership remains for existing holders. The calculator therefore limits the input to below 100%.
Treat it as a consistency check between valuation, check size, and target ownership. A legal cap table should still be prepared for the actual financing documents.