How to Read the Order Book and Trade History
Understand market depth, bid/ask spreads, and recent trade activity to make informed trading decisions.
The order book is the live list of what people are willing to pay and accept; the trade history is what actually happened. Together they tell you how much size the market can absorb before the price moves — which is the only question that matters before sending an order larger than a few hundred dollars.
Before you start
- A trading pair open. The book is readable without any balance, which makes it a good place to practise.
Locate the Order Book
On the trading screen, the order book is displayed as a two-sided list. The upper half (red) shows sell orders (asks) listed from lowest to highest price. The lower half (green) shows buy orders (bids) listed from highest to lowest price. The center shows the current market price.
Read Bid and Ask Prices
Each row in the order book shows a price level and the quantity of the asset available at that price. Bids represent prices buyers are willing to pay. Asks represent prices sellers are willing to accept. The difference between the best bid and best ask is called the spread.
Assess Market Depth
The cumulative bars behind the order book rows represent market depth, the total volume of orders at or better than each price level. Thicker green bars suggest strong buying support, while thicker red bars suggest strong selling pressure. This visualization helps you gauge how much liquidity exists at each level.
View Recent Trades
The trade history panel shows recently executed trades for the selected pair. Each entry displays the price, quantity, and timestamp. Green entries indicate the trade was executed at the ask price (buyer-initiated), while red entries indicate execution at the bid price (seller-initiated).
Use This Information for Trading
A tight spread and high depth indicate a liquid market where orders fill easily with minimal slippage. A wide spread or thin order book may result in higher slippage for market orders. Use the order book and trade history together to time your entries and set appropriate limit prices.
If something goes wrong
- The book looks almost empty.
- That is genuinely thin liquidity on that pair, and market orders there will slip badly. Use limit orders, smaller size, or a more liquid pair.
- Large orders appear and vanish repeatedly.
- Resting orders can be cancelled at any time, and some are placed with no intention of filling. Treat depth as a snapshot, not a promise.
Frequently asked questions
- What is the spread telling me?
- The gap between the best bid and the best ask is the immediate cost of a round trip. A wide spread is the clearest sign of a thin market.
- Why is the book green and red?
- Bids — orders to buy — on one side, asks to sell on the other. The colouring is convention, the information is the price and the size at each level.
- Does trade history predict direction?
- It records what has traded, not what will. It is useful for judging activity and typical trade size, not for forecasting.