Enter Series A Round Details
Example Data Table
| Input | Example Value | Meaning |
|---|---|---|
| Pre-money valuation | $12,000,000 | Company value before new money |
| Investment amount | $4,000,000 | Cash invested in Series A |
| Founder shares | 7,000,000 | Shares held by founders |
| Existing option pool | 800,000 | Reserved employee incentive shares |
| Other shares | 1,200,000 | Seed, advisor, or early holder shares |
| Target option pool | 12% | Desired pool after the round |
| Estimated top-up | 761,904.76 | Extra pool shares needed before closing |
| Investor ownership | 25% | New investor stake after closing |
Formula Used
The calculator uses a fully diluted ownership model. Current shares equal founder shares plus existing option shares plus other existing shares.
Current Shares = Founder Shares + Existing Option Shares + Other Existing Shares
If a target post-round option pool is entered, the calculator estimates the top-up shares with this equation.
Top-Up = ((Target Pool × (1 + Investment ÷ Pre-Money) × Current Shares) − Existing Option Shares) ÷ (1 − Target Pool × (1 + Investment ÷ Pre-Money))
The price per share is calculated after adding the option top-up to the pre-money share base.
Price Per Share = Pre-Money Valuation ÷ Adjusted Pre-Money Shares
Investor Shares = Investment Amount ÷ Price Per Share
Post-Round Shares = Adjusted Pre-Money Shares + Investor Shares
Ownership % = Holder Shares ÷ Post-Round Shares × 100
How to Use This Calculator
- Enter the pre-money valuation from the proposed term sheet.
- Add the new Series A investment amount.
- Enter founder shares, existing option shares, and other existing shares.
- Set the target post-round option pool percentage.
- Add any planned employee grant shares for extra impact analysis.
- Enter the liquidation preference multiple when needed.
- Press the calculate button.
- Review ownership results above the form.
- Download the result table as CSV or PDF.
Series A Dilution Planning Guide
A Series A round changes the ownership map of a company. Founders usually focus on cash raised. Investors focus on price, percentage, and future room for hiring. This calculator joins those parts into one view. It estimates the new investor stake, the price per share, the option pool top up, and the post round cap table. Always confirm final structures carefully with counsel. Legal documents may define share counts differently during closing reviews and negotiations.
Why dilution matters
Dilution is not always bad. A founder may own less after the round, while the company becomes worth more. The key question is balance. The new money should support growth that can offset the lower percentage. A clear model helps founders compare offers before signing term sheets.
How the option pool affects ownership
Many Series A deals ask for a target option pool after the financing. If the pool is created before the investment, the cost is usually carried by existing holders. That means founders and earlier shareholders may dilute more than the new investor. This calculator solves the required top up when a target post round pool is entered.
Important inputs to review
Start with a realistic pre money valuation. Add the planned investment amount. Enter current founder shares, existing option pool shares, and other shares. Then add the desired post round option pool percentage. The model also accepts an employee grant size, so you can estimate the percentage impact of a planned hiring grant.
Reading the results
The price per share is based on the pre money value divided by the adjusted pre money shares. New investor shares are then calculated from the investment amount. The post round total includes old shares, the option top up, and new investor shares. Ownership percentages are based on that final total.
Using the calculator for negotiation
Run several scenarios before making decisions. Compare a smaller raise at a higher valuation with a larger raise at a lower valuation. Change the option pool target to see how sensitive founder ownership becomes. Export the results, then share the table with advisors, cofounders, or legal counsel. The numbers are estimates, but they create a useful starting point for informed round planning.
FAQs
What is Series A dilution?
Series A dilution is the ownership reduction caused by new investor shares and possible option pool expansion during a Series A financing round.
Does dilution always mean founders lose value?
No. Founders may own a smaller percentage, but their remaining stake can become more valuable if the investment increases company growth and valuation.
What is a pre-money valuation?
Pre-money valuation is the agreed company value before new investment cash is added. It helps determine the share price for the round.
What is a post-money valuation?
Post-money valuation is pre-money valuation plus the new investment amount. It shows the company value immediately after the financing closes.
Why does the option pool top-up matter?
A pre-round option pool top-up usually dilutes existing holders. It can lower founder ownership before the new investor receives shares.
Can this calculator model employee grants?
Yes. Enter planned employee grant shares. The calculator estimates their percentage impact against the post-round share count.
Is the investor ownership always investment divided by post-money valuation?
It often matches that result when the round is simple. Option pool terms, share counts, and special structures can change practical outcomes.
Should I use this result as legal advice?
No. This calculator gives planning estimates. Always confirm final share counts, securities terms, and legal documents with qualified professionals.