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Fund size & ownership calculator

The arithmetic every LP runs on a venture pitch, before the meeting. See whether your fund size, check size and ownership target are actually consistent.

Venture fund size is a strategy statement, not just a fundraising target. This calculator shows the relationship between check size, target ownership, expected portfolio size, and the reserve ratio set aside for follow-on investment — the same arithmetic LPs run before ever seeing your deck.

Strategy inputs

Initial check size $1,000,000

Target initial ownership 10%

Number of initial (new) positions 25

Reserve ratio (for follow-ons) 50%

Implied fund

Implied post-money valuation per deal—

Capital into initial positions—

Reserve capital (follow-ons)—

Implied total fund size—

Avg. total capital per company (w/ follow-on)—

This calculator is for general illustration only. It ignores taxes, fund-specific mechanics and edge cases in your actual documents. It is not financial, legal or tax advice — check figures against your fund's actual governing documents.

Why this arithmetic matters to LPs

LPs run this exact calculation before deciding whether a fund's stated strategy is internally consistent. If your reserve ratio and portfolio size imply a fund size well above or below what you're actually raising, that's a mismatch an experienced allocator will spot immediately — either the fund can't support its own stated follow-on strategy, or the check size and ownership targets aren't realistic for the fund size. More on how LPs diligence fund sizing →

The reserve ratio here is expressed as reserves relative to total capital — a 50% reserve ratio means for every dollar into new positions, an equal dollar is set aside for follow-ons, roughly doubling the initial-position capital to reach the implied total fund size.

Frequently asked questions

How is venture fund size related to ownership targets?

Fund size is a function of check size, the number of positions the fund intends to make, and the reserve capital set aside for follow-on investment. If any of these are set inconsistently — for example a large ownership target with a small fund size and a high position count — the arithmetic simply doesn't work, which is exactly what LPs check first.

What is a reserve ratio?

The proportion of a venture fund's capital set aside for follow-on investments in existing portfolio companies, rather than new initial positions. A common range is 40-60%, though it varies by strategy and stage — under-reserving is one of the most common structural errors in emerging venture funds.

Why do LPs check this arithmetic before a pitch meeting?

Because an oversized fund relative to its stated check size and ownership target cannot plausibly return capital from the outcomes achievable at that stage, and LPs have seen this mismatch often enough to check it immediately as a basic filter.

Should a fund maximise ownership per deal?

Not necessarily — higher ownership targets mean fewer total positions for a given fund size, which increases concentration risk. The right ownership target depends on stage, conviction level, and how much diversification the strategy needs.

What happens if a fund is undersized relative to its reserve strategy?

The fund will run out of capital to defend its ownership in follow-on rounds, diluting its position in its best companies exactly when protecting that position matters most — a common and costly planning error for emerging managers.

Does this calculator work for later-stage or growth funds?

The same mechanics apply, though later-stage funds typically use larger check sizes, lower position counts, and different reserve assumptions given fewer, larger follow-on rounds — adjust the inputs accordingly.

Nothing on this page is legal, tax, or investment advice. SeRuM is not a registered broker-dealer, not a placement agent, and not an investment adviser.

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