Deep-dive guide
Founder Dilution Simulator: What Your Stake Is Worth After Every Round
Executive industry analysis
Dilution is the price of growing with other people's money. Every time a company sells shares, the founders keep the same number of shares but own a smaller percentage of a larger company. That trade is usually worth making: a smaller slice of a company that is ten times bigger is worth more. The mistake is not dilution itself but failing to see how it compounds, because several rounds, an option pool and investor protections all take a portion before the founders see anything at exit.
The structure of the problem has three layers. The first is the share of the company sold, determined by the amount raised and the valuation. The second is the option pool, which is often created before the investment so that founders, not the new investors, bear it. The third is the sequence of later rounds. On top of ownership there is a separate question of who gets paid first. Investors often hold a one-times liquidation preference, so in a modest exit the money they put in comes out before the common shares are paid.
The domino model follows this in five steps. The first round sells a share of the company set by raise and valuation. That, with the option pool and later rounds, gives your ownership at exit. Compared with the exit value, the money invested shows how heavy the preference overhang is. The after-tax value of your stake follows, and spread across a five-year horizon it gives a monthly figure to compare with the salary you give up. A weak valuation, a large pool or one extra round can each cut ownership noticeably.
The iceberg shows what the cap table hides. Above the waterline is the after-tax stake value per month and the salary you gave up. Below it is the value lost to the option pool you funded, the value taken by each later round, the value lost when investors choose their preference instead of converting, and the tax on proceeds. These are easy to miss because no one sends an invoice. Use the simulator to find the exit value or the combination of rounds at which the stake no longer rewards the years of work.
Formula and methodology blueprint
The model calculates the founder's after-tax value at exit and spreads it over a five-year horizon, then subtracts the monthly salary given up compared with a market job. The first round sells raise divided by post-money. The option pool takes its share of the post-round company from existing holders. Each later round sells about eighteen percent, with round sizes growing two and a half times each time. Investors take the greater of their one-times preference and their converted share, and the common shareholders split what remains.
- First-round dilution
- d = raise ÷ (pre-money + raise)
- The share of the company sold to the new investors in the first priced round.
- Existing holders after the round
- E = (1 − d − pool) × 0.82^(rounds − 1)
- What founders and early holders keep after the pool and every later round.
- Founder ownership
- F = founder share × E
- Your percentage of the company at exit.
- Investor take
- T = min(exit, max(total invested, investor share × exit))
- Investors convert if that pays more than their one-times preference; otherwise they take their money back first.
- Monthly value
- Net = F ÷ (1 − investor share) × (exit − T) × (1 − 20% tax) ÷ 60 − salary gap
- The after-tax stake spread over sixty months, less the pay given up.
Cascading elasticity
Exit value and ownership are the most elastic inputs because the result is their product. Valuation matters most among the deal terms, since it sets how much is sold in the first round. The number of rounds compounds, so each added round costs more than the last in absolute terms. The option pool is a steady cost. Round size matters indirectly through both dilution and the preference stack, which can swallow a small exit.
Three real-world case studies
Bootstrapped starter
A single seed round with a clear majority
A founder holding eighty percent raises half a million at a four and a half million valuation, plans no further rounds and exits at thirty million. Dilution is modest and the stake is worth a good deal. Load it to see how a small, well-priced round keeps ownership high.
Scaling mid-market
A well-priced company that raises three times
A founding team with a forty-five percent share raises a large first round at a sixty million valuation and two more rounds before a six hundred million exit. Ownership falls but the outcome is large. Load it to see that heavy dilution can still pay when the exit is big.
Black-swan crisis
Four rounds on a small exit
A founder holding forty percent raises on a low valuation with a twenty percent option pool, goes through four rounds and sells for twenty million. Investors' preferences exceed the sale price. Load it to see the founder walk away with nothing despite owning a large stake on paper.
Industry benchmark matrix
| Metric | Danger zone | Industry average | Top 10% elite |
|---|---|---|---|
| Seed round dilution | Above 30% | 15–25% | Below 15% |
| Option pool (post-round) | Above 20% | 8–15% | Sized to a real hiring plan |
| Founder ownership after Series A | Below 35% combined | 50–60% combined | Above 65% combined |
| Dilution per later round | Above 25% | 15–20% | Below 12% |
| Total invested versus exit value | Above 60% | 20–35% | Below 15% |
Variables and levers
First round size
Amount raised in the first priced round. Later rounds are assumed to be larger, each about two and a half times the previous one.
Lever: Raise only what the next milestone needs, because each extra dollar sold early costs the most ownership.
Pre-money valuation
Company value agreed before the new money goes in. A higher figure means less of the company is sold.
Lever: Build traction and competing interest before you price the round, since valuation is the most powerful lever on dilution.
Option pool
Share of the post-round company reserved for employee options, usually created before the investment so that founders carry the dilution.
Lever: Size the option pool to the real twelve-month hiring plan instead of a round number, and negotiate it as part of the valuation.
Funding rounds before exit
Total priced rounds until the company is sold. Each later round is assumed to sell about 18% of the company.
Lever: Plan the path with fewer, better-timed rounds and use revenue to reach milestones, because every extra round multiplies dilution.
Exit value
Price at which the company is sold or listed at the end of the five-year horizon.
Lever: Keep exit value in view: a smaller stake of a much larger outcome usually beats a larger stake of a small one.
Founders' share before the round
Share of the pre-round company held by you, after co-founders and early holders.
Lever: Settle vesting and co-founder splits early and fairly, because the stake you start with sets everything that follows.
How to use this simulator
- 1Enter the first round size and the pre-money valuation you are negotiating.
- 2Set the option pool, your share before the round and the number of rounds you expect.
- 3Enter a realistic exit value rather than the best case.
- 4Press Find my breaking point to see which term hurts your payout most.
- 5Compare the current plan with a smaller raise and one fewer round over 24 months.
Mistakes to avoid
- Focusing on valuation alone. A higher price with a larger pool, heavy preferences or participation rights can leave you with less than a lower, cleaner price.
- Ignoring the next rounds. Ownership after the first round is not ownership at exit, and each new round adds its own pool top-up and terms.
- Treating paper value as cash. In a modest sale the preference stack may take most of the price, and the common shares receive little.
- Assuming the best-case exit. Model a lower exit as well, because that is where terms matter most.
Frequently asked questions
Is dilution bad?
Not by itself. You trade a share of ownership for capital that can make the company far more valuable. It becomes a problem when you give up too much too early or fail to model the rounds ahead.
Why does the option pool dilute founders only?
It is usually created before the new money, so it reduces the pre-money value that belongs to existing holders. Negotiating the pool size is a way to negotiate the valuation.
What is a liquidation preference?
A right for investors to receive their invested money, usually one times, before common shareholders in a sale. It matters most when the exit is small compared with the money raised.
Why is tax included?
To give a value closer to what you keep. The rate here is only an illustration; tax rules differ by country and structure, so check current rules or ask an adviser.
How do I find the breaking point?
Press Find my breaking point. The tool moves each input toward its worse end and reports the value where the monthly value reaches zero.
How accurate is this?
It is an educational model with simplified rounds, not legal, tax or investment advice. Real terms include anti-dilution clauses, participation rights and vesting; read your term sheet with a lawyer.
This is an educational planning model with stated assumptions. It is not financial, tax or legal advice. Replace the inputs with your own figures and verify important decisions with a qualified professional.