These two numbers sit side by side on nearly every coin listing, and it's easy to conflate them. They're measuring genuinely different things, and mixing them up leads to misreading the market.
Market capitalization
Market cap is price multiplied by circulating supply. It's a snapshot of the total value of every coin currently in circulation, and it's the standard way coins are ranked by size. A high market cap generally signals an established asset, but it says nothing on its own about how easy that asset is to actually buy or sell right now.
Trading volume
Volume measures how much of an asset actually changed hands over a period — usually the last 24 hours — expressed in a quote currency like USD. High volume signals liquidity: it's easier to enter or exit a position without moving the price much. Low volume, even on a coin with a large market cap, can mean wider spreads and more price impact per trade.
Why the ratio between them matters
Comparing volume to market cap (sometimes called a turnover ratio) gives a sense of how "active" a coin's trading is relative to its size. A small-cap coin with volume that's a large fraction of its market cap is seeing unusually intense trading activity relative to its size — which is part of the signal CryptoHeat's Trending section uses, alongside price momentum.
The practical takeaway
Use market cap to gauge an asset's overall size and standing. Use volume to gauge how liquid and actively traded it is right now. A coin can be large by market cap and quiet by volume, or small by market cap and extremely active by volume — and those are two very different situations to be aware of.