Your cap table is an Excel file. The math is wrong.
Most early-stage cap tables live in Excel or Google Sheets. They work, until the priced round, when the SAFE conversion math gets done by hand, the formulas drift across versions, and the cap table no longer matches the share register. By the time you discover the gap, you've already sent the wrong percentages to investors. This page is the honest case for moving off spreadsheets.
Specific scenarios where spreadsheet cap tables produce wrong answers, SAFEs, conversions, options.
Why a spreadsheet can't be the share register, and what happens when you treat it as one.
What a real cap-table system does that a spreadsheet can't, and at what price.
Spreadsheets are universal. Cap tables are statutory.
Excel and Google Sheets are excellent calculation tools. They are not cap tables. The distinction matters because a cap table is not just a calculation, it is a representation of statutory share ownership, tied to specific issued certificates, traceable to specific board resolutions, with mathematical consequences for every shareholder, option holder, and SAFE investor.
A spreadsheet doesn't know any of that. It knows numbers and formulas. The structure, the consistency with the underlying share register, the audit trail, the validation of SAFE conversion math, none of it exists unless you build and maintain it yourself, every time, manually.
The pattern we see most often: the cap table works fine through seed, then breaks at Series A, usually during the financing itself, when the SAFE conversions get worked through by hand and the founder discovers the math doesn't match what investors were told.
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SAFE conversion math gets done wrong
Post-money SAFEs, MFN provisions, batch conversions at priced rounds, the formulas are intricate. Hand-rolled spreadsheets get them wrong in 30-40% of cases we audit. The errors are typically not caught until the round closes.
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The cap table doesn't match the share register
The corporation maintains a 'cap table' in Excel and a 'share register' (also Excel) separately. Over years of issuances and transfers, the two diverge. By the time diligence asks for both, they don't reconcile.
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No record of who changed what
Who updated the option pool last? When? Why? The spreadsheet doesn't know. A 'last modified' timestamp is all you get. Investor-facing changes go unverified.
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Version chaos
Cap_Table_FINAL_v3_post_round.xlsx. Cap_Table_FINAL_v3_post_round_corrected.xlsx. Cap_Table_FINAL_v4_after_BoD.xlsx. By month 18, no one knows which version is current.
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Options and warrants are an afterthought
Each option grant is a row, plus a vesting schedule in another sheet, plus a calculation of fully-diluted that may or may not include them. The instruments are forced into rows that weren't designed for them.
What a real cap table system does
If you're considering whether to move off a spreadsheet, here's the test. Real systems handle these; spreadsheets approximate them.
- First-class instruments. SAFEs, convertible notes, options, warrants treated as objects with their own properties, not crammed into rows.
- Batch SAFE conversion at priced rounds. When the priced round closes, all outstanding SAFEs convert in one operation with the cap/discount math handled correctly.
- Tie to the share register. The cap table is generated from the share register, not maintained alongside it. They cannot drift apart.
- Scenario modeling. A-vs-B comparisons for term sheets, dilution modeling, exit waterfalls, without hand-rolling formulas.
- Activity log per change. Who changed what, when, why, and at whose authorization. Every change attributable.
- Public share links with revocation. Send a cap table to an investor with a link. See who opened it. Revoke if the term sheet falls through.
The SAFE conversion is the most common failure point.
If you've issued SAFEs and haven't yet been through a priced round, here's what awaits: at the round, your counsel will work through the conversion of every outstanding SAFE, applying the cap or discount (whichever is more favourable for the investor), accounting for MFN provisions, and reconciling the result against the option pool and the new investor's percentage.
The math is exact and recursive. Post-money SAFEs lock in percentages of the post-money cap, so adding more SAFEs dilutes the founders rather than earlier SAFE holders. Pre-money SAFEs (the old YC form) dilute each other and the founders. Mixed cap structures, MFN-triggered amendments, and option pool top-ups before the round all compound the complexity.
Hand-rolled spreadsheet conversions produce errors in roughly a third of cases we audit. The errors are typically not caught until founders realize their post-round percentage doesn't match the term sheet, which is when the lawyers have to re-do the math under time pressure during closing.
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Wrong cap basis
Post-money SAFE caps apply to the post-money capitalization. Pre-money SAFEs (old YC form) apply to pre-money. Spreadsheets often blur this, producing dilution math that's off by several percentage points.
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Missing MFN cascades
If a later SAFE has more favourable terms, earlier MFN-bearing SAFEs automatically inherit them. The spreadsheet doesn't know to recalculate the earlier SAFEs.
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Option pool order errors
Whether the option pool top-up happens before or after the SAFE conversion changes the math. Term sheets specify one; spreadsheets often model the other.
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Discount vs. cap selection
The investor gets the more favourable of cap or discount. Spreadsheets often hard-code one path, picking incorrectly in some scenarios.
A spreadsheet can't be the statutory record.
Beyond the math, there's a more fundamental problem. The cap table in Excel isn't the corporation's statutory share register, it's a summary downstream of it. The statutory record (the share register or stock ledger under CBCA s. 50, DGCL § 219, UK CA 2006 s. 113) is a separate document, maintained somewhere else.
When the cap table spreadsheet and the share register disagree, the register controls. So if the spreadsheet says one thing about a shareholder's holding and the register says another, the register wins, even if everyone has been operating on the basis of the spreadsheet for years. This is how diligence-stage surprises happen.
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Voting rights
Determined by the register, not the cap table. If they disagree, the register wins.
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Dividend entitlement
Distributions go to register holders. A wrong spreadsheet doesn't redirect them.
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Inspection rights
Standing to inspect (under § 220, s. 21, etc.) depends on being on the register, not the cap table.
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Tax basis
Capital gains, QSBS qualification, Section 85 rollovers, all depend on the register, not the cap table.
Spreadsheets vs. a real cap table system
Where the two diverge when stakes are real.
When to move off spreadsheets
Spreadsheets work fine for very early stage. Here's when they stop working.
The conversion math is where spreadsheets break. The first SAFE is the right moment to move; the third or fourth is when the failure surfaces.
Counsel will work through the cap table with you in detail. If it's a spreadsheet, plan for the closing to involve last-minute math corrections.
Vesting schedules, exercises, repurchases, terminations, each one is a chance for the spreadsheet to drift. A real system tracks each grant as an object with its own lifecycle.
Common + Series A + Series B + options + SAFEs in one spreadsheet is operationally manageable. Add liquidation preferences and the formulas become impossible to maintain.
If your corporate counsel has suggested moving to a real system, take the hint. They've seen the failure modes more recently than you have.
Multiple corporations with related cap tables, Section 85 rollovers, internal share transfers, well past the point where any spreadsheet structure holds.
Common questions
Free tier for one corporation. Growth plan ($59/mo annual) adds SAFE conversion and scenario modeling. Migration from Excel takes 1-2 hours.