Open any asset popup on our tracker and you will find a figure labelled market cap — sometimes in billions, sometimes in trillions. It is the standard answer to the question "how big is this company?", yet it is widely misunderstood, starting with the most common confusion of all: the share price.
The calculation
Market capitalisation is simply the share price multiplied by the number of shares that exist. A company with two billion shares trading at fifty dollars each has a market cap of one hundred billion dollars. That is the market's collective, minute-by-minute estimate of what the whole company is worth.
Why share price alone tells you nothing
A share priced at one thousand dollars is not from a bigger company than a share priced at ten dollars. The thousand-dollar company may have very few shares; the ten-dollar company may have billions of them. Comparing share prices between companies is like comparing two cakes by the size of a single slice while ignoring how many slices each was cut into. Market cap fixes this by counting all the slices.
This is also why stock splits do not create value: cutting the cake into more, smaller slices changes the share price but leaves market cap untouched.
Large, mid and small caps
Investors sort companies into size tiers because size correlates with behaviour. Large caps — the giants worth tens or hundreds of billions — tend to be stabler, widely followed and slower-growing. Small caps are more fragile and more volatile, but the rare ones that succeed can multiply many times over. Mid caps sit between. Major indices are usually weighted by market cap, which is why a handful of enormous companies can drag an entire index up or down on their own.
Market cap in crypto
The same formula applies to cryptocurrencies — coin price multiplied by circulating supply — and the same misunderstanding follows. A coin priced at a fraction of a cent is not automatically "cheap": if trillions of units exist, its market cap may already be enormous, leaving little room for the fantasy of it "reaching a dollar". Whenever a coin's price looks temptingly tiny, check its market cap on our tracker before imagining multiples.
The limits of the number
Market cap measures the equity value the market assigns; it ignores a company's debts and its cash. Two companies with equal market caps can be in very different financial health. Professionals often adjust for this, but as a first-glance measure of scale, market cap remains the most useful single number on the page — as long as you remember what it does and does not include.