# What Is Market Capitalization? A Plain-English Guide

> Market capitalization is a company's share price times its shares outstanding. Here's how it works, what it tells you, and what it leaves out.

Source: MarketCapLens — https://www.marketcaplens.com/learn/what-is-market-capitalization
Updated: 2026-05-11

Market capitalization (or "market cap") is what the stock market says a company's shares are worth in
total. You calculate it by multiplying the share price by the number of shares outstanding. It is the
standard way to measure how big a public company is, and it is the number that orders every row in the
[MarketCapLens ranking](https://www.marketcaplens.com/).

**Key takeaways**

- Market cap = share price × shares outstanding.
- It measures a company's size, not whether it is a good investment.
- It ignores debt and cash, which is where [enterprise value](https://www.marketcaplens.com/learn/market-cap-vs-enterprise-value) comes in.
- Share price alone tells you nothing about size; a $30 stock can be a bigger company than a $300 one.

## How is market cap calculated?

The formula is short:

> **Market cap = share price × shares outstanding**

So if a company trades at $200 a share and has 1.5 billion shares outstanding, its market cap is
**$300 billion** ($200 × 1.5B). Share prices move all day, so market cap does too. That is exactly why
a ranking by market cap keeps reshuffling.

There is one wrinkle worth knowing. Plenty of large companies issue **more than one class of shares**,
such as a voting and a non-voting class. To value the whole business you add up every class. On
MarketCapLens, a company's share classes are combined so it appears once, at its true size — see
[dual-class shares and market cap](https://www.marketcaplens.com/learn/dual-class-shares-and-market-cap).

## What market cap tells you

Market cap lets you compare companies with very different share prices on equal footing. A $500 stock
is not "more expensive" than a $50 stock in any way that matters; what counts is the combined value of
all the shares. (That trips up a lot of people, so we gave it
[its own guide](https://www.marketcaplens.com/learn/market-cap-vs-stock-price).)

Size also hints at how established and heavily traded a company is likely to be. The conventional bands,
from mega-cap down to micro-cap, are laid out in [the size tiers](https://www.marketcaplens.com/learn/market-cap-size-tiers).
For industry groupings, see [what a sector is](https://www.marketcaplens.com/learn/what-is-a-sector).

## What market cap leaves out

Market cap values a company's **equity** and nothing else. Two things it quietly ignores can matter a
lot:

- **Debt.** A company that borrows heavily can look modest by market cap yet be far larger once its
  obligations are counted.
- **Cash.** A big cash pile effectively makes a company cheaper than its market cap implies, because a
  buyer would get that cash.

To fold both into the picture, investors turn to **enterprise value**. We put the two side by side in
[Market Cap vs. Enterprise Value](https://www.marketcaplens.com/learn/market-cap-vs-enterprise-value).

Market cap is also silent on profits, growth, and quality. Two companies of the same size can earn
wildly different amounts. Think of market cap as a measure of size and market sentiment, not a verdict
on whether a stock is worth buying.

## How investors use market cap

- **Index weighting.** Major indexes like the S&P 500 lean on market cap, so the largest companies move
  the index the most.
- **Screening and ranking.** Sorting by market cap is the usual first step when you want the biggest
  companies in a market or [sector](https://www.marketcaplens.com/sectors).
- **Curated groups.** Cohorts such as the [Magnificent 7](https://www.marketcaplens.com/magnificent-7-stocks) are really just a few
  of the very largest companies by market cap.

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*For general education only. Nothing here is investment advice.*

## Frequently asked questions

### How do you calculate market capitalization?

Multiply the current share price by the total number of shares outstanding. A company trading at $200 a share with 1.5 billion shares has a market cap of $300 billion.

### Is a higher market cap always better?

No. Market cap measures a company's size, not its quality or value. A larger company is not automatically a better investment than a smaller one.