Market Cap in Crypto: The Number Everyone Quotes and Almost No One Checks Properly
How market capitalisation is actually calculated, why it's a far weaker signal than it looks, and the low-cap trap it sets for less experienced buyers.
By Firoz Khan|14 September 2026|Updated 26 September 2026|4 min read
Market capitalisation gets treated as a straightforward measure of size and credibility, quoted on every ranking table without much scrutiny. The calculation behind it is genuinely simple, which is exactly why it's easier to distort than most people assume.
The calculation is simple, that's the problem
Market cap is current price multiplied by circulating supply, nothing more. For a coin with thin actual trading activity, a handful of trades at an inflated price can push the calculated market cap far above what the asset could realistically be sold for in bulk, because the figure reflects the last traded price, not the depth of demand behind it.
Circulating vs total vs max supply
Circulating supply is what's actually in the market and tradeable today. Total supply includes coins that have been created but aren't yet in circulation, often locked with the team or reserved for future release. Max supply is the absolute ceiling the protocol will ever allow to exist, if one is defined at all. A coin can look artificially scarce today while a large tranche of supply sits ready to be released later, diluting existing holders when it lands.
A worked example
Say a token trades at £0.50 with 10 million tokens in circulation. Its market cap is £5 million. But the project has a total supply of 100 million, with the other 90 million locked and due to be released over three years. Priced at the same £0.50, all 100 million tokens would be worth £50 million, which is often called the fully diluted valuation. If 20 million tokens unlock next month, circulating supply triples from 10 million to 30 million. Unless demand grows to match, the same buying power is now spread across three times as many tokens. The numbers are examples, not a real project.
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Why a 'small market cap' isn't automatically a bargain
The small-cap comparison to stocks is tempting but misleading: a small-cap company usually has revenue, assets and a balance sheet underneath its share price. A small-cap token, more often than not, has none of that, its price reflects pure speculation about future adoption rather than any current fundamentals, which is a structurally different kind of bet.
The liquidity trap
A token can show a market cap of tens of millions on paper while the actual depth available to trade at that price, without moving it significantly, is a fraction of that figure. A relatively modest sell order can crash the price of a thinly traded token within minutes, which is precisely the scenario 'low market cap, huge upside' marketing tends to leave out.
Say that £5 million market cap sits on an order book with only £30,000 of buy orders close to the current price. Selling £30,000 of tokens could push the price down sharply, and nobody could sell the whole £5 million at the quoted price. Market cap tells you what the last trade multiplied by the supply comes to, not what the holdings could be sold for.
A better way to use the number
Treat market cap as one input among several, alongside actual trading volume, how concentrated ownership is among a small number of wallets, and whether the project solves a problem people are demonstrably paying to use, rather than as a standalone signal of quality or safety on its own.
Checking the number yourself
Price tables usually show circulating, total and maximum supply, so compare them. Read the project's own documents for its unlock schedule, and check how much of the supply sits with a few wallets. Compare 24-hour trading volume with the market cap: a large market cap with tiny volume is a warning sign.
In the UK, crypto promotions should carry prominent risk warnings, and the FCA says you should be prepared to lose all the money you put into crypto. A pitch built on "low market cap, huge upside" that leaves the risk warning out is not following those rules.
A reminder
The FCA risk warning still applies to higher-risk crypto content. Always assess how much risk you are willing to take before buying.
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