How to read a crypto order book
A beginner's guide to bids, asks, spread, depth and order walls
The order book is the list of all open buy and sell orders for a trading pair, such as BTC/USDT, sorted by price. It shows where traders are ready to buy and sell right now. Learning to read it helps you see liquidity, support and resistance before they show up on a price chart.
Bids and asks
An order book has two sides:
- Bids are buy orders. Buyers want to pay this price or less. Bids sit below the current price, with the highest bid on top.
- Asks (offers) are sell orders. Sellers want to get this price or more. Asks sit above the current price, with the lowest ask closest to it.
Each row is a price level with the total size of all orders at that price. Many exchanges also show a running total, which tells you how much volume you would need to push price to that level.
The spread
The spread is the gap between the best bid and the best ask. On liquid pairs like BTC/USDT it is often a single tick. A wide spread means fewer orders near the price, so a market order will move the price more.
Market orders and limit orders
Limit orders rest in the book and add liquidity: they are what you see as bids and asks. Market orders take liquidity: a market buy eats asks from the lowest price up, a market sell eats bids from the highest price down. Every trade you see in the trade feed is a market order hitting resting limit orders.
Market depth
Depth is how much volume stands on each side within a price range. If bids within 1% of the price hold much more volume than asks, buyers have more resting interest close to the price. Depth changes constantly, so traders watch how it moves, not a single snapshot.
Order walls
A wall is an unusually large order, or a cluster of orders, at one price. A big bid wall can act as support: price has to absorb all that volume to fall through. A big ask wall can act as resistance. When a wall gets eaten and price breaks through, the move often speeds up.
Spoofing: walls that disappear
Not every wall is real. Some large orders are placed to create an impression of support or resistance and are cancelled before price reaches them. This is called spoofing. Watching which walls get filled and which get pulled is one of the most useful order book skills.
What the order book cannot tell you
- Hidden and iceberg orders are not fully visible.
- The book shows one exchange only; other exchanges can trade at the same time.
- Orders can be cancelled in milliseconds, so a static picture can mislead.
See the order book as a battle
Columns of numbers that change many times per second are hard to follow. Order Book War shows the live Binance order book as a battle of bulls and bears:
- bears at the top are asks, bulls at the bottom are bids, and the glowing front line is the price;
- a squad is a price level, and bigger levels bring heavier troops;
- a spear phalanx is a wall;
- arrows and shurikens are market trades;
- a fallen warrior is a filled order, and a ghost is a cancelled one — the easiest way to notice spoofing.
Try it free in the browser on the home page or get the app on Google Play.
This guide is educational and is not investment advice. Cryptocurrency trading involves risk.