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Cap table dilution calculator.

Model a priced round and see how ownership shifts across founders, existing investors, new investors, and the option pool. Add as many existing holders as you want — results recalculate live.

  • Add unlimited founders, employees, and existing investors
  • See pre-round vs. post-round ownership side by side
  • Pool top-up taken out of pre-money (the standard market convention)
  • Optional emailed PDF if you want to save the scenario
Open the calculator
Inputs & results

Edit any field. Results update instantly. Defaults model a typical Series A: $3M into a $12M pre-money with a 10% pool top-up.

Existing holders (pre-round)
Priced round
$
$
%
Top-up comes out of the pre-money cap (founder dilution). Set equal to the existing pool % to skip the top-up.
Round math
Post-money valuation
—
Round price per share
—
New investor ownership
—
Total existing-holder dilution
—
Holder Shares Before After
Optional · Save this scenario
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We’ll send a clean PDF with the pre-round and post-round cap tables side-by-side, plus the round assumptions you used.

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How the math works

Pre-money pool top-up, then new money.

This calculator follows the standard market convention: the option pool top-up dilutes existing holders before the new money lands.

1
Post-money = pre-money + new money

Total company value after the round equals the pre-money valuation plus the new cheque size. Simple arithmetic, but every other number flows from this one.

2
Pool top-up lands first

Investors require the option pool to be at the target percentage on a post-money basis. The top-up gets created out of the pre-money cap, diluting existing holders.

3
Round price per share

Pre-money valuation divided by the pre-money fully-diluted share count (including the top-up). That sets the price the new investors pay.

4
New investor shares

New money divided by round price = new shares issued. They join the cap table at face value; existing holders are diluted proportionally.

After the round closes

A modelled cap table isn’t a real cap table.

The calculator gives you the shape of the round. But once the wire lands, you need to issue certificates, record the issuance in your share register, file the board resolutions, and update the corporate records — in the right order, with the right paperwork. Octelligence does all of that from one source of truth.

See Cap Tables & Financing
FAQ

Common questions

No — by convention, the pool top-up is created pre-money and dilutes only existing holders. Investors set the pool target as a percentage of the post-money cap so that their ownership is unaffected by the top-up. The calculator follows that convention. If your term sheet specifies a post-money pool, the new investor takes the dilution and the round price is higher.

This calculator models a clean priced round — no SAFE or note conversion. If you have outstanding SAFEs, run them through the SAFE conversion simulator first to get the post-conversion share count, then bring those shares into this calculator as an existing holder.

So you can see the dilution directly. Pre-round percentages reflect ownership before the top-up and the new money; post-round percentages reflect the final cap table including everything. The delta between the two columns is the dilution each holder absorbs.

The page itself can be bookmarked; your inputs persist in the form fields while the tab is open. For a sharable artifact, request the emailed PDF report above. Most users send it to a co-founder or counsel to align on the numbers before signing a term sheet.

It’s accurate for modelling. It does not replace a closing cap table prepared by counsel, which will reflect the exact share counts, par values, certificate numbers, and class structure that go into the formal corporate records. Use this to negotiate; use a real cap-table system — like Octelligence — to close.
Related concepts

The glossary behind the math.

Definitions for every term the calculator uses, plus sibling tools for SAFE conversions and corporate records.

Cap table
Who owns what, fully diluted
Option pool
Pre-round top-up and dilution
Preferred stock
The class new investors typically receive
Common stock
What founders and employees hold
Anti-dilution
Protection against down rounds
Liquidation preference
Payout ordering on exit
Option Pool / ESOP Planner
Compare pre vs post-money pool top-up cost
SAFE Conversion Simulator
Model SAFEs before they hit the cap table
Multi-SAFE Batch Simulator
Convert a stack of SAFEs at one round
Corporate Records Health Check
See if your records will survive diligence
Full glossary
86 terms across corporate records and equity
Stop running cap tables on spreadsheets.

Octelligence runs your cap table, share register, and certificates from one source of truth. Issuances reconcile automatically, certificates are QR-verified, and diligence packs build themselves.

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