Dilution Maths: What Each Round Actually Costs (2026)
A virtual CFO walks founder dilution from seed to Series B: pre and post-money, the option-pool shuffle, SAFEs, and what each 1 per cent is worth at exit.
Founders raise on valuation and are diluted by mechanics, and the two are not the same thing. A headline valuation feels like the number that matters, but the ownership a founder actually keeps is decided by post-money maths, option-pool timing, and how earlier instruments convert. Most founders discover the real cost of their rounds only when they add it up at the end. This is a virtual CFO’s walk through the arithmetic, in founder terms, so the cost is visible before each round rather than after all of them.
Published: July 2026
Dilution comes down to a few mechanics worth stating plainly. A round has a pre-money valuation (what the business is worth before the new money) and a post-money valuation (pre-money plus the amount raised). The investor’s ownership is the amount they put in divided by the post-money valuation. So a $2M investment at an $8M pre-money is $2M on a $10M post-money, giving the investor 20 per cent, and diluting the existing holders by that 20 per cent collectively.
The price per share is the post-money valuation divided by the fully diluted share count, and it is the number that actually governs how much of the company each dollar buys. Founders tend to fixate on the valuation and ignore the share count and the fully diluted base, but dilution is fundamentally about shares issued relative to shares outstanding. Understanding it in share terms, not just valuation terms, is what makes the option-pool shuffle below visible, and it is a natural part of a fundraise-ready financial model and a 90-Day Number ahead of raising.
The single most underappreciated source of dilution is the option pool, and specifically its timing. Investors typically require an option pool for future hires, and they usually require it to be created or topped up pre-money, meaning the pool is carved out of the existing shareholders’ ownership before the investor’s money goes in. This is the option-pool shuffle, and it dilutes the founders more than the headline round terms suggest.
Here is why it matters in numbers. Suppose a round is done at an $8M pre-money and the investor also requires a 10 per cent post-money option pool created pre-money. That pool comes out of the pre-money value, so the effective pre-money for the founders is reduced by the pool, and the founders bear the full dilution of creating it while the investor’s stake is protected from it. A founder who reads only the valuation sees an $8M pre-money; a founder who reads the term sheet sees that the pool shuffle has quietly increased their dilution by several percentage points. The lesson is not that pools are wrong, they are necessary to hire, but that where the pool is created, and out of whose ownership, is a negotiable term with a real cost that the founder should see clearly.
Put the mechanics together and walk a founder’s ownership across rounds. Start at 100 per cent at founding. A seed round selling, say, 15 to 20 per cent (including a pool) takes the founder to roughly 80 per cent. A Series A selling around 20 per cent, with a pre-money pool top-up on top, takes the founder down further, often to somewhere in the low-to-mid 60s per cent once the pool shuffle is included. A Series B selling another 15 to 20 per cent takes the founder into roughly the 40 to 50 per cent range, depending on round sizes, pool top-ups, and how much was sold at each stage.
These figures are illustrative, not a rule, because the actual path depends on how much is raised at each round relative to valuation and how large the pools are. But the shape is consistent and worth internalising: a founder who raises a normal seed, A, and B, and gives up a normal pool at each, typically holds something in the 40 to 50 per cent range by the end of Series B, before any further rounds. For context on Australian round sizing, recent market data puts typical medians in the region of $1M at pre-seed, a few million at seed, and around $11M at Series A, which shapes how much ownership each of those rounds tends to cost. The walk makes the cumulative cost of the journey visible, which is the thing a single round’s terms never show.
Many early rounds are raised on SAFEs (simple agreements for future equity) rather than priced rounds, and SAFEs complicate the walk because they do not dilute until they convert. A SAFE raised at seed sits off the visible cap table until the next priced round, when it converts into shares at its cap or discount, and that conversion dilutes the founder at the moment it happens, often by more than the founder remembered agreeing to. Stacking several SAFEs at different caps makes the eventual conversion hard to predict without modelling it.
The discipline is to model the SAFEs into the walk before the priced round, so the founder sees what the conversion will do to their ownership rather than being surprised by it when the round closes. A founder who has raised on SAFEs and never modelled the conversion frequently over-estimates how much of the company they still hold, because the SAFEs are invisible until they bite. Modelling them into the cap table walk is the only way to see the true position. The detail of SAFE mechanics is covered further in the fundraise and exit material.
The reason all this arithmetic matters is that each percentage point of ownership has a value at exit, and the walk lets a founder put a number on what they are giving up. If a founder plausibly exits the business at, say, $50M, then each 1 per cent of ownership is worth $500,000 at that exit. Seen that way, the option-pool shuffle that quietly cost three extra points of dilution cost the founder $1.5M of exit value, and the SAFE conversion that took five points cost $2.5M.
This is not an argument against raising or against pools; capital and hires drive the growth that creates the exit value in the first place. It is an argument for seeing the cost clearly, so the founder can weigh each round’s dilution against what it buys and negotiate the terms, pool size and timing especially, that have a real dollar value. A founder who understands that a term-sheet detail is worth a million dollars at exit negotiates it differently from one who sees only the headline valuation. The questions to ask before signing, how big is the pool, is it pre or post-money, what do existing SAFEs convert into, are the ones that protect real value. Anything touching the legal terms themselves belongs with a lawyer; the arithmetic here is what tells the founder which terms to focus the lawyer on.
What is the difference between pre-money and post-money?
Pre-money is what the business is worth before the new investment; post-money is pre-money plus the amount raised. The investor’s ownership is their investment divided by the post-money valuation. A $2M investment at an $8M pre-money is 20 per cent of a $10M post-money, diluting existing holders by that 20 per cent collectively.
What is the option-pool shuffle?
The practice of creating or topping up the employee option pool pre-money, so it is carved out of existing shareholders’ ownership before the investor’s money goes in. This means founders bear the full dilution of the pool while the investor’s stake is protected from it, increasing founder dilution by several points beyond what the headline round terms suggest. Where the pool is created is a negotiable term with real cost.
How much of my company will I have left after Series B?
Illustratively, a founder who raises a normal seed, A, and B, giving up a normal pool at each, typically lands in the 40 to 50 per cent range by the end of Series B, before any further rounds. The exact figure depends on round sizes relative to valuation and pool top-ups, but the shape is consistent: normal rounds plus normal pools cost roughly half the company by Series B.
How do SAFEs affect dilution?
SAFEs do not dilute until they convert, usually at the next priced round, at their cap or discount. That conversion dilutes the founder at the moment it happens, often more than remembered, and stacking several SAFEs at different caps makes the conversion hard to predict. Founders who never model the conversion tend to overestimate how much they still hold, because SAFEs are invisible until they bite.
What is each 1 per cent of my company worth?
It depends on the exit value. At a $50M exit, each 1 per cent is worth $500,000, so three points of extra dilution from a pool shuffle costs $1.5M and a five-point SAFE conversion costs $2.5M. Seeing dilution in dollar terms is what turns a term-sheet detail into a negotiation worth having, because the terms have a real, quantifiable value.
Should I avoid dilution?
No, capital and hires drive the growth that creates exit value, so dilution is the price of building something bigger. The point is to see the cost clearly and negotiate the terms, pool size and timing especially, that carry real dollar value, rather than fixating on the headline valuation and ignoring the mechanics that actually determine what you keep.
Can a virtual CFO model my dilution?
Yes. A cap-table walk from your current ownership through the rounds ahead, including the option-pool shuffle and any SAFE conversions, with each point valued against plausible exits, is a defined deliverable and a natural 90-Day Number ahead of raising. The output is a model you own that shows the true cost of each round. Legal terms themselves stay with your lawyer; the arithmetic tells you which terms to focus on.
Sydney Virtual CFO is a Sydney-based virtual CFO service for founders running $2M to $15M businesses across SaaS, ecommerce, professional services, construction, and other low-volume, high-value industries. We deliver fixed-scope CFO engagements with a named deliverable on day 90: a 13-week cashflow forecast, a fundraise-ready financial model, a unit economics build, or a board reporting pack you can run on your own.
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This content is general information only, written for Australian founders running businesses in the $2M to $15M revenue range. It does not constitute tax, financial product, investment, or legal advice and should not be relied on as such. The work referenced is led by a Chartered Accountant (CA ANZ), but Sydney Virtual CFO is not a licensed tax agent, not a licensed financial adviser, and not authorised to provide personal financial advice. Tax obligations, accounting treatments, fundraise terms, and statutory requirements depend on your individual circumstances. For advice specific to your business, contact the team directly or consult a registered tax agent, licensed financial adviser, or qualified lawyer. Information was current at the time of publication and may change without notice. We review and update guides periodically.
