Reading a depth chart: the order book as a picture

An order book lists waiting orders price by price. A depth chart draws the same information as two curves, so you can see liquidity at a glance.

The two sides

• The green curve on the left shows bids (buy orders), added up from the best bid downward.
• The red curve on the right shows asks (sell orders), added up from the best ask upward.
• The gap between them in the middle is the spread.

Each point answers: how much would I have to sell (or buy) to push the price to this level?

What to look for

• Steep curves near the middle mean a lot of liquidity close to the price: large orders move the price little.
• Flat curves mean thin liquidity: even small orders can move the price.
• Walls — sudden vertical steps — are large orders at one price. They may slow the price there, but they can be cancelled at any moment.
• Asymmetry — more liquidity on one side — shows where more orders are waiting right now, not where the price will go.

Estimating price impact

To estimate the effect of a market buy, follow the ask curve until the cumulative amount equals your order. The price at that point is roughly the worst price your order would reach.

Limits

The chart shows one exchange at one moment. Orders appear and disappear constantly, and some are placed only to create an impression. Use the depth chart together with the order book, trades and price chart. On XFasil, the order book of each Spot screen updates live — read Reading an order book.

This is general education. XFasil does not provide trading operations or investment advice; the Spot and Futures screens show market data only.