Cap Table Basics: How to Build and Read One

A cap table (short for capitalization table) is the single source of truth for who owns what in a company. It lists every shareholder, option holder, and warrant holder, converts them all into a common "fully diluted" share count, and shows each holder's ownership percentage. Get the cap table wrong and everything downstream - fundraising math, option grants, exit proceeds - breaks. This guide walks through the mechanics of building one in Excel, how to read an existing one, and a full worked example across two priced rounds.

Founders usually meet their first cap table the moment they incorporate: a spreadsheet with two rows and 8,000,000 shares split evenly. It stays simple for about six months. Then an option pool gets carved out, a SAFE converts, a priced round closes, and suddenly the spreadsheet needs to track authorized shares, unallocated pool, vesting schedules, and price-per-share math across multiple rounds simultaneously. Most of the confusion founders run into - "wait, why did my ownership drop by 5% and I didn't sell anything?" - comes down to not understanding fully diluted share count and how new rounds dilute it.

From authorized shares to a fully diluted, post-round ownership table

What a Cap Table Actually Tracks

A capitalization table is a ledger, not a spreadsheet trick. Every row is a security someone holds, and every column answers a question an investor, auditor, or founder will eventually ask:

The most common misread of a cap table is looking only at issued and outstanding shares and ignoring the option pool. A founder with 4,000,000 of 8,000,000 outstanding shares looks like they own 50%. But if there's also a 1,500,000-share option pool sitting on the cap table (allocated or not), their real ownership is 4,000,000 / 9,500,000 = 42.1%. Cap tables are always read on a fully diluted basis for this reason.

The Four Share Counts You Need to Keep Straight

1. Authorized shares - the maximum number of shares the company's charter permits it to issue. Set once at incorporation, amended by board/shareholder vote.
2. Issued shares - shares that have actually been granted or sold, whether to founders, investors, or employees who've exercised options.
3. Outstanding shares - issued shares still held by shareholders (excludes any repurchased or cancelled shares).
4. Fully diluted shares - outstanding shares plus every option, warrant, and unallocated pool share that could become a share. This is the denominator for every ownership percentage calculation.

Founders and early employees almost always underestimate the option pool's drag on their percentage because it's counted in the denominator even before it's granted to anyone.

Common Stock vs. Preferred Stock and Liquidation Preferences

Not every row on a cap table carries the same rights. Founders and employees typically hold common stock. Investors in priced rounds typically hold preferred stock, which layers on contractual protections common stock doesn't have - most importantly a liquidation preference.

A liquidation preference determines who gets paid first, and how much, before remaining proceeds are split by ownership percentage. The standard structure is "1x non-participating": in an exit, each preferred investor gets back the greater of (a) their original investment, or (b) what their ownership percentage would entitle them to if all shares converted to common. Multiple rounds of preferred stack in reverse order - the most recent round is typically paid out first, then earlier rounds, then common.

This matters for cap table modeling because fully diluted ownership percentage and exit proceeds are not the same thing in a low-value exit. A Series A investor who owns 20% fully diluted still gets their $5,000,000 back first (their liquidation preference) before any proceeds flow to common, even if 20% of the actual sale price would have been less than $5,000,000. Only once total proceeds clear the preference stack does the ownership-percentage split apply the way the fully diluted table implies. Modeling this properly requires a dedicated exit waterfall - the cap table itself just needs to record each round's preference terms (1x, 2x, participating vs. non-participating) as an input for that later analysis.

Building the Model: Sheet Structure

A cap table model in Excel typically splits into four linked sheets:

1. Shareholders - one row per holder: common stock, preferred by round, grant dates.
2. Option Pool - total pool size, allocated grants (with vesting schedules), unallocated remainder.
3. Financing Rounds - pre-money valuation, investment amount, price per share, new shares issued, for each round in sequence.
4. Fully Diluted Summary - pulls from the first three sheets to show current ownership %, and a dilution waterfall showing how ownership shifted round over round.

As with any financial model, no security's share count or price should be hardcoded on the summary sheet - every cell should trace back to the Shareholders, Option Pool, or Financing Rounds inputs.

Vesting Formula

Most employee option grants vest over four years with a one-year cliff, then monthly thereafter. In Excel, given a grant's total shares and months employed as of the reporting date:

// Vested shares: 4-year vest, 1-year cliff, monthly thereafter
= IF(Months_Employed < 12, 0, MIN(Total_Grant, Total_Grant * Months_Employed / 48))

Before month 12, nothing vests - the cliff. At month 12, 25% vests immediately (12/48). After that, 1/48th vests each additional month, capped at the full grant.

Ownership Percentage Formula

// Fully diluted ownership %
= Shares_Held / Total_Fully_Diluted_Shares

Price Per Share (Priced Round)

// Price per share = pre-money valuation / pre-money fully diluted shares
= Pre_Money_Valuation / Pre_Money_Fully_Diluted_Shares

// New shares issued to investor
= Investment_Amount / Price_Per_Share

These three formulas are the entire engine of a cap table model. Everything else - the summary table, the dilution waterfall, the ownership chart - is built by referencing them.

Worked Example: Seed Round

Let's build a cap table from incorporation through a Seed round.

At incorporation, two founders split 8,000,000 shares of common stock evenly - 4,000,000 each, 100% ownership between them, no option pool yet.

Immediately before the Seed round closes, the investors require a 1,500,000-share option pool to be carved out of the pre-money structure - standard practice, since it signals there's room to hire without diluting the new investor:

The company raises a $2,000,000 Seed round at an $8,000,000 pre-money valuation ($10,000,000 post-money).

Price per Share = Pre-Money Valuation / Pre-Money Fully Diluted Shares
Price per Share = $8,000,000 / 9,500,000 = $0.8421

New Shares Issued = Investment / Price per Share
New Shares Issued = $2,000,000 / $0.8421 = 2,375,000 shares

Post-Seed cap table:

Check the math two ways: the Seed investor put in $2M of a $10M post-money company, so they should own exactly 20% - and 2,375,000 / 11,875,000 = 20.00%. It ties.

Worked Example: Series A and the Dilution Waterfall

Eighteen months later, the company raises a $5,000,000 Series A at a $20,000,000 pre-money valuation ($25,000,000 post-money), with no new option pool top-up this round.

Pre-Money Fully Diluted Shares (carried forward) = 11,875,000

Price per Share = $20,000,000 / 11,875,000 = $1.6842

New Shares Issued = $5,000,000 / $1.6842 = 2,968,750 shares

Notice the Series A price per share ($1.6842) is exactly 2.0x the Seed price ($0.8421) - a clean "2x step-up," the metric investors use to gauge how much value the company created between rounds.

Post-Series A cap table and full dilution waterfall:

No shareholder sold a single share between these snapshots - the founders' combined stake dropped from 100% to 53.89% purely through dilution, as each new round issues shares out of a growing denominator. This is the core mechanic every founder needs to internalize before raising money: valuation growth and ownership dilution happen simultaneously, and a "good" round is one where your slice shrinks but the pie grows fast enough that your dollar value still goes up.

How to Read a Cap Table as an Employee or Investor

If you're evaluating an offer letter or an investment, you're usually handed a snapshot of someone else's cap table, not building your own. A few questions get you to the real picture fast:

• "What's the fully diluted share count?" An offer of "10,000 shares" is meaningless without the denominator. 10,000 shares of 10,000,000 fully diluted (0.10%) is very different from 10,000 shares of 100,000,000 (0.01%).
• "What's the strike price, and what's the most recent 409A valuation?" For options, the strike price is typically set at the 409A fair market value at grant. A wide gap between strike price and the last priced round's valuation implies more embedded value in the option - but also more risk if the company's value has declined since.
• "How big is the unallocated option pool, and is it about to be topped up?" A large unallocated pool sitting on the cap table represents dilution that hasn't happened yet but will, as it gets granted to future hires.
• "What's the liquidation preference stack?" For investors, know what preferred rounds sit ahead of you and at what multiple (1x, 2x) and structure (participating or non-participating) - it determines your actual payout in a modest exit, not just your fully diluted percentage.
• "When does vesting start, and is there a cliff?" A grant with vesting start backdated to an early date is more valuable than one starting today, since less of the four-year clock remains.

Every one of these questions is answerable directly from a well-built cap table - which is exactly why keeping one current and complete, rather than reconstructing it under time pressure during a financing or acquisition, is worth the discipline.

Common Mistakes to Avoid

1. Reading outstanding shares instead of fully diluted shares. The option pool (even unallocated) belongs in the denominator. Skipping it overstates everyone's real ownership.
2. The "option pool shuffle." Some investors negotiate for the option pool to be expanded pre-money - meaning existing shareholders (mostly founders) absorb 100% of the dilution from the new pool shares, while the incoming investor's post-money percentage is untouched. Know whether a pool top-up is happening pre- or post-money before agreeing to a term sheet.
3. Forgetting SAFEs and convertible notes in the fully diluted count. Uncoverted SAFEs don't show up as "shares" until they convert at the next priced round, but they represent real, near-certain future dilution. Model them as if-converted shares so the fully diluted count isn't a surprise later.
4. Confusing pre-money and post-money valuation when computing price per share. Price per share always uses pre-money valuation over pre-money fully diluted shares - using post-money numbers in either the numerator or denominator silently changes the deal.
5. Not separating allocated vs. unallocated option pool shares. Both count toward fully diluted shares, but only allocated grants have vesting schedules and named holders - mixing them up breaks headcount planning.
6. Treating the cap table as a static document. Every new hire, option grant, exercise, and financing round changes it. A cap table that isn't updated within days of an event is a liability the moment anyone - an investor, an acquirer, an auditor - asks to see it.