See exactly how much your ownership stake shrinks — and what it's worth — after a new funding round.
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| Metric | Before Round | After Round |
|---|
An equity dilution calculator shows founders, early employees, and early investors exactly what happens to their ownership stake when a company issues new shares to raise a priced funding round. NeftCal's free equity dilution calculator works from just four inputs — your current shares, total shares outstanding before the round, the pre-money valuation, and the new investment amount — and returns your ownership percentage after the round, the dilution in percentage points, your stake's dollar value at the post-money valuation, and the post-money valuation itself.
Raising money is almost always good for the company, but it always comes with a cost to percentage ownership: new investors receive newly issued shares, the total share count grows, and every existing shareholder's slice of the pie shrinks proportionally. This tool makes that math concrete rather than abstract, so you can evaluate a term sheet, plan a round, or check your equity position with real numbers instead of guesses.
This tool is useful for startup founders modeling how a seed, Series A, or later round will dilute their ownership; early employees who hold options or grants and want to know what their percentage will be worth after the next raise; angel investors and venture firms estimating the percentage their investment will buy; and advisors or anyone negotiating equity who needs a quick, defensible dilution figure before a term sheet is signed.
Founders often see a shrinking percentage and assume it is automatically bad news — but dilution and value destruction are not the same thing. Because the valuation typically rises alongside the new investment, a smaller slice of a bigger pie can be worth the same or more than a bigger slice of a smaller one. This is exactly why the calculator reports your stake's dollar value after the round, not just your percentage. The pre-money valuation is the main lever in all of this: it sets the price per share and therefore how much of the company the new money buys. To estimate that valuation before you model a round, use the business valuation calculator and then bring the figure here to see its dilution consequences.
New shares issued to investors dilute every existing shareholder proportionally
New investment usually raises the total valuation, so a smaller percentage slice can still be worth the same or more in dollar terms.
Price per Share, derived from the pre-money valuation, determines how many new shares get created — and therefore how much everyone else is diluted.
Investors often require an option pool top-up before the round, which adds extra dilution not modeled by a simple new-investment calculation.
From your share position to a full dilution breakdown in under a minute
Input the number of shares you personally hold before the round. This stays fixed through the calculation — dilution comes from the total growing, not from your count shrinking.
Input the total shares outstanding before the new round. For the most realistic result, use the fully diluted count — issued shares plus outstanding options and warrants.
Input the company's valuation before the new money is added. This is the number that sets the price per share and therefore how many new shares the round creates.
Input the total amount the round will raise from new investors. Larger raises at the same valuation mean more new shares and more dilution for existing holders.
The results panel shows your ownership percentage after the round, the dilution in percentage points, your stake's value at the post-money valuation, and the post-money valuation itself.
Read the breakdown table comparing total shares, your shares, ownership percentage, and stake value before and after the round, and use Export Result to save a plain-text summary.
A realistic funding round for a growing startup, step by step
Suppose you are a co-founder holding 1,000,000 shares out of 8,000,000 total shares outstanding before the round. The company has an $8,000,000 pre-money valuation and is raising $2,000,000 from a venture firm — the same inputs the calculator loads by default, so you can reproduce every number.
Explanation: The new investors put in $2,000,000 of a $10,000,000 post-money valuation, so they own 20% of the company and you own 10.00% — down from 12.50%. Your stake's dollar value stays at $1,000,000 because the investors are modeled as paying exactly the pre-money price per share of $1.00: your percentage falls from 12.50% to 10.00% (a 20% relative drop), while the post-money valuation rises by 25% ($8M to $10M), which exactly offsets the smaller percentage. In this model the price per share is always derived from the pre-money valuation, so a priced round preserves existing shareholders' value in dollars — the percentage dilutes while the value holds.
Sanity check: the compact formula agrees with the step-by-step math. New Owner % = $2,000,000 ÷ $10,000,000 = 20%. Founder's New % = 12.50% × ($8,000,000 ÷ $10,000,000) = 12.50% × 0.80 = 10.00%. If the same $2,000,000 round instead closed at a $6,000,000 pre-money, your ownership would drop to 9.375% and the value of your stake would fall from $1,000,000 to $750,000 — which is why pre-money is the number founders negotiate hardest on.
What your dilution and stake value actually tell you
The two numbers worth reading together are your ownership percentage after the round and the dollar value of your stake at the post-money valuation. The percentage shows how much of the company you control going forward; the dollar figure shows whether that control is worth more or less in real terms. These are general reference bands, not a formal industry standard.
| Dilution per Round | General Read | Typical Context |
|---|---|---|
| Under 10 pp | Light dilution | Large pre-money, small raise, or a high price per share |
| 10 – 25 pp | Common range | Typical priced rounds across seed and venture stages |
| Over 25 pp | Heavy dilution | Large raises, low pre-money, or a round with a big option pool refresh |
For ownership percentage after: this is the number that matters for control, board dynamics, and future option grants. It is the percentage your cap table records, and it is what you negotiate to protect.
For dilution in percentage points: the gap between before and after. A 2.50 percentage-point drop on a 12.50% stake is a 20% relative reduction, so read both the points and the relative change — a small point figure can still be a large relative loss on a small stake.
For stake value after: compare it with your stake's value before the round. If it is higher, the valuation growth more than offset the dilution; if it is lower, the round priced at a discount to what you held, and you should understand why before accepting the terms.
Risk considerations: this model assumes a priced round at the pre-money price per share, with no option pool top-up, no convertible conversions, and no preferred-share features. Real rounds often include these, so treat the result as a planning estimate to stress-test, not a guarantee.
This calculator provides estimates for educational and informational purposes only. Results may vary depending on business conditions, accounting methods, taxes, market trends, and other factors. It should not be considered financial, legal, tax, accounting, or investment advice. Consult qualified professionals before making business decisions.
Where this startup dilution calculator earns its keep
Model a seed or Series A round before you ever talk to an investor, so you know your dilution in advance.
Convert a proposed pre-money and investment amount into the concrete dilution and stake value it produces.
Track how successive rounds erode your percentage and plan the ownership you want to preserve.
Estimate what your option grant or restricted stock will be worth after the next raise.
Run quick what-ifs before updating your cap table after any priced round.
Test how much you'd give up at different pre-money valuations before you counter an offer.
Sanity-check valuation terms by converting them into a percentage of the company sold.
Estimate the extra dilution an option pool refresh will add on top of the new investor shares.
Chain several rounds to see cumulative dilution over the company's next few raises.
Estimate the ownership percentage your investment will actually buy before committing.
Check how a lower valuation round affects both your percentage and the dollar value of your stake.
Align expectations by showing how future funding will shift everyone's ownership percentages.
What this equity dilution calculator does well, and where it can't replace a formal cap table or legal advice
Two sides of the same deal — and the terms that drive how much dilution a round produces
| Measure | Pre-Money Valuation | Post-Money Valuation |
|---|---|---|
| Definition | Company value before the new investment | Company value after the new investment |
| Formula | An input you provide | Pre-Money + New Investment |
| What it drives | Price per share and new shares issued | The new investors' ownership percentage |
| Effect on dilution | Lower pre-money means more shares issued for the same raise — more dilution | Higher post-money means the raise buys a smaller ownership slice |
| Why it matters | The number founders negotiate hardest on | The number that tells you what percentage you gave away |
Estimate the pre-money valuation itself with the Business Valuation Calculator, then bring the figure here to see exactly how much dilution the round produces at that valuation.
Common questions about equity dilution and startup ownership
Official guidance to complement this calculator — not a substitute for legal or financial advice
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