Order book crypto: how to read bids, asks and depth

What an order book shows on a crypto exchange

On a crypto exchange, an order book is a live listing of every current buy and sell order for one trading pair, say, bitcoin against the euro. You’re seeing what others want to pay or accept right now. This list updates the moment anyone places, fills, or cancels an order. Buy orders are called bids. Sell orders are called asks, or sometimes offers. The highest bid and the lowest ask meet in the center, with the difference (the spread) hinting at what it costs for an instant deal. Not every app shows you this. Some brokers set their own rates and just display a single price for your trade, since you’re not being directly matched with another customer.

How to read bids, asks and market depth

Most order books you’ll see display three main columns: price, the coin amount at each price, and a running total. Layout and colors depend entirely on the platform, so check the labels before you act. Market depth refers to how much can change hands near today’s going price. When an order book is deep, many orders close to the middle, a larger trade won’t swing the price much. In a thin book, though, even a modest order can move the market.

Check the top levels for the best bid and best ask.
Scroll down or up to spot the volume stacked at higher or lower rates.
Use the depth chart if available; it visually plots cumulative volume on both sides.

Why the order book matters before a larger trade

The order book gives you a concrete sense of liquidity, that is, how easily you can buy or sell without shifting the price too much. In crypto, prices can move fast, so it’s a practical step, but you don’t want to rely on it alone when there’s money at stake.

If your purchase or sale would use up all the coins available at the best price, the rest of your order will fill at the next best level, and so on. You might end up paying a blended price that’s higher than the best ask or lower than the best bid. This price difference is called slippage. By placing a limit order, you can set your maximum or minimum, see market vs limit orders for the details. Orders left in the book actually add liquidity and can get a different fee structure from so-called taker trades, which grab what’s already there. There’s more on this under maker vs taker fees.

Worked example: buying into a thin order book

Say you find 10 coins for sale at 100 euros each, and another 40 at 101 euros each. If you send in an order to buy 25 coins at market price, here’s what happens: 10 fill instantly at 100 euros, which totals 1,000 euros. The next 15 come from the orders at 101 euros, costing 1,515 euros. Paid altogether, that’s 2,515 euros for 25 coins, averaging 100.60 euros per coin. That 0.60 above the best ask shows how price can slip. These numbers just show the principle, not a real-life quote.

Frequently asked questions

Is the order book the same on every exchange?

No, it isn’t. Each exchange maintains its own book, with its own flow of users and orders. So the prices and depth you see can easily differ between platforms, even for the same cryptocurrency. You need to check the book on the platform you plan to use, the situation can shift within seconds.

What is the difference between a bid and an ask?

A bid stands for an offer to buy at a specific price. An ask is an offer to sell at the seller’s chosen price. The highest bid together with the lowest ask highlights the current spread. Orders waiting in the book provide liquidity. Orders that fill those, take it away.