Depth of market is the quantity of displayed buy and sell orders at different price levels in an order book. A depth view can show the best bid and ask, order sizes, and cumulative quantity farther from the midpoint.
Reading a Depth View
A trader can sum displayed bids or asks within a chosen price range to estimate how much visible size rests near the market. For example, the displayed ask depth from $65,000 to $65,100 may total 12 BTC. A 3 BTC market buy could consume part of that displayed quantity, subject to changes in the book and execution priority.
The snapshot does not show all potential liquidity. Participants can cancel orders, hidden quantity may not appear, and other venues may have different books. A displayed order can change before a trade reaches it.
Limits of Order Book Data
Depth is a view of limit orders at a point in time. It does not prove that price will hold at a level or that displayed size will trade. Aggregated views can also depend on venue selection, contract conversion, and update timing.
Depth is useful for describing visible liquidity and planning execution assumptions. It does not predict price direction by itself. Read Order Book, Spread, Liquidity, and Slippage for related mechanics.