What Is Market Cap in Crypto?

Market cap, short for market capitalization, is the number most crypto data sites use to rank coins. It tells you how big a coin’s market is, not whether the coin is a good buy. If you are new to crypto, start with our guide to what cryptocurrency is.

This guide works through the formula with real bitcoin figures, explains the supply numbers behind it and shows where it can mislead. To see prices in practice, check a coin’s price with the crypto calculator.

What is market cap in crypto?

Crypto market cap is the current price of one coin multiplied by the number of coins in circulation. CoinMarketCap and CoinGecko, two widely used crypto data sites, both calculate it this way (as of September 2026).

Market cap = price of one coin × circulating supply

It is usually shown in US dollars, based on a price such as BTC/USD. Read how crypto trading pairs work.

A worked example with bitcoin

On 28 September 2026, CoinGecko showed these figures for bitcoin:

• Price: about $83,370 per bitcoin.
• Circulating supply: about 20.09 million BTC.
• Market cap: $83,370 × 20.09 million ≈ $1.67 trillion.

The market cap moves every time the price moves, and rises slowly as new coins are mined (see the Bitcoin halving). These figures are a snapshot, not a current price. Past performance does not predict future results.

What is the difference between circulating, total and max supply?

Circulating supply is the number of coins in public hands today. Total supply is every coin created so far, minus coins that were burned (permanently destroyed). Max supply is the most coins that can ever exist (CoinMarketCap definitions, as of September 2026).

Market cap uses circulating supply. For bitcoin, circulating and total supply are the same, because mined coins are not locked away. Many newer tokens hold back a large share for the team, early investors or a treasury and release it over time. CoinGecko deducts these locked tokens when it works out circulating supply (as of September 2026). See our glossary entry on circulating supply.

Supply is also hard to measure. Lost bitcoins still count, because they stay on the blockchain like any other coins (Bitcoin.org), and no one knows exactly how many are lost. CoinMarketCap calls circulating supply “an imperfect approximation”. Ether has no fixed maximum: new ETH is issued to validators, and part of every transaction fee is burned (ethereum.org).

What is fully diluted valuation (FDV)?

Fully diluted valuation (FDV) is what a coin’s market cap would be if its full supply were in circulation at today’s price. It uses a bigger supply number, so it is always equal to or higher than market cap.

Data sites do not agree on which supply to use. CoinMarketCap multiplies the price by max supply, or by total supply when there is no max supply. CoinGecko uses total supply (both as of September 2026). So on 28 September 2026, bitcoin’s FDV was about $1.67 trillion by CoinGecko’s method, the same as its market cap, but about $1.75 trillion by CoinMarketCap’s method, which counts all 21 million coins.

A big gap between FDV and market cap means many coins are still to come. In a made-up example, a token has 1 billion units, but only 200 million circulate. At $2 each, its market cap is $400 million and its FDV is $2 billion. If the other 800 million are released and demand does not keep up, each token becomes a smaller share of the whole, which can push the price down. CoinGecko itself describes FDV as a projection that ignores demand. Before you buy a newer token, check its unlock schedule.

Why can market cap mislead?

Market cap multiplies the latest trading price by every coin in circulation, although only a small share of coins trades on any day. So it is not what holders could cash out.

• Only a small share trades. On 28 September 2026, about $42.5 billion of bitcoin traded in 24 hours, around 2.5% of its market cap (CoinGecko). If many holders sold at once, the price would drop, and the market cap with it.
• Thin trading moves small coins. With little trading, a few orders can move a coin’s price, and its market cap, a long way. That makes small coins easier to push up and down, as in pump-and-dump schemes. Read what liquidity means and why crypto prices are volatile.
• Supply can be self-reported. Circulating supply often comes from the project team. CoinMarketCap labels figures it has not verified as “self-reported” (as of September 2026). A wrong supply number gives a wrong market cap.
• Sites use different data. On 28 September 2026, CoinGecko put the total crypto market cap at about $2.95 trillion, while CoinMarketCap showed about $2.86 trillion. Use one site when you compare coins.

How does market cap work for stablecoins?

A stablecoin’s market cap mostly shows how many tokens are in circulation, because its price is designed to stay close to $1. It grows when the issuer creates tokens, not because the price rises.

On 28 September 2026, Tether (USDT) had about 183.8 billion tokens in circulation at about $1.00 each, a market cap of about $183.8 billion and the third largest on CoinGecko. Stablecoins as a group were worth about $308 billion, around 10% of the total crypto market cap.

A steady price is not the same as no risk. In May 2022, the TerraUSD (UST) stablecoin lost its link to the US dollar, and its price fell close to zero (US SEC). Read what a stablecoin is and what Tether (USDT) is.

Is a coin with a low price cheap?

No. The price of one coin says little on its own, because coins have very different supplies. Compare market caps instead.

On 28 September 2026, one dogecoin (DOGE) cost about $0.09 and one bitcoin almost 900,000 times more (CoinGecko). Yet bitcoin’s market cap, about $1.67 trillion, was only about 115 times dogecoin’s $14.6 billion. The reason is supply: about 156 billion DOGE were in circulation, against about 20 million BTC.

A low price usually reflects a large supply, not a bargain. A million tokens at $0.0001 are worth $100, the same as about 0.0012 BTC at $83,370. What matters is the value of what you hold, not the number of coins.

What do large-cap and small-cap mean in crypto?

They are informal labels for coins with a large or a small market cap. Crypto has no official cut-off points: data sites simply rank coins from the largest market cap to the smallest.

Larger coins usually trade more, so a single order moves their price less. That does not make them safe. On 28 September 2026, bitcoin, the largest coin, was about 34% below its all-time high of about $126,080, set on 6 October 2025 (CoinGecko). Smaller coins often swing even more, and some lose almost all their value. Past performance does not predict future results.

What is Bitcoin dominance?

Bitcoin dominance is bitcoin’s market cap as a share of the total crypto market cap. On 28 September 2026, CoinGecko put it at about 56.6%.

Because stablecoins count in the total, new stablecoin issuance can lower bitcoin dominance even when bitcoin’s price does not change. Read our guide to Bitcoin dominance and what it shows, and learn about the rest of the market in what altcoins are.

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Malcolm O'Mahony

Malcolm is a Content Marketing Manager at Coinmama. He's passionate about Web3 and specializes in making complex concepts easy to understand. Crypto since 2017. Coinmama since 2020.

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