How to Read the Order Book: What It Shows Next to a Chart, and Where It Misleads

Why keep the order book next to the chart

A chart groups trades that have already happened into candles; the order book stacks orders that have not been filled yet by price level. The first is a record of the past, the second is a snapshot of who is waiting at which price right now. How to place orders and how market and limit orders differ is covered in the crypto topic's article on the order book and order types, so this article is not about placing orders. It focuses on what you gain, and what you are likely to be fooled by, when you read the order book while watching a chart. The reason to look at both screens is simple: you can check whether orders are really stacked at a level that looks like support or resistance on the chart, and whether those orders hold when a breakout is attempted or disappear first. The order book, however, shows intent, not outcome. A resting order can be cancelled at no cost until it is filled, so what the book says changes much more easily than what the chart says. Keep that difference in mind from the start.

Definition and formulas: spread, mid price and depth ratio

The upper (or right) side of the book holds asks, limit orders to sell; the lower side holds bids, limit orders to buy. The lowest ask and the highest bid are the best quotes, and the gap between them is the spread. A spread in price units cannot be compared across assets, so it is common to divide it by the mid price and express it as a percentage. The depth ratio measures what share of the total size within the visible levels sits on the bid side, and the number changes a lot depending on how many levels you include. Korean brokerage screens usually show 10 levels on each side, crypto exchanges each show a different number of levels, and this site's order book dashboard looks at the top 20 levels and at 500 levels separately. At the same moment the 20-level ratio and the 500-level ratio often point in opposite directions, so whenever you quote a ratio, note how many levels it covers. The formulas are below.

• Spread = best ask − best bid
• Mid price = (best ask + best bid) ÷ 2
• Spread % = spread ÷ mid price × 100
• Depth ratio = sum of bid size in visible levels ÷ (bid size + ask size)

How to read it: lay resting size over chart levels

The basic way to read the book with a chart is to line up locations. First mark the recent highs and lows, heavily traded volume zones and the prices where key moving averages run, then check whether the quotes near those prices carry thicker size than usual. If a large bid sits just below a support line on the chart, there are orders willing to defend that level, at least for now; if the bid side near support is empty, the line may be thinner than it looks. Next, look at the spread. A spread wider than usual means liquidity has thinned, so price can jump on small orders and candles tend to grow long wicks. Finally, watch how resting size changes as price approaches. Size that grows as price comes closer is closer to genuine willingness to trade; size that shrinks or steps back one level at a time as price nears raises the suspicion that it is there for show. A volume zone is where trading was heavy in the past and resting size is what is waiting now, so a level matters more when the two overlap.

Order walls: what thick size does and does not do

An order wall is a price where far more size is resting than around it. If those orders are real, they absorb market orders when price reaches them and slow the move, which leaves repeated wicks or shrinking candles near that price on the chart. A wall being eaten shows up in the trade list as a run of fills at that price while the resting size falls. Once the wall is consumed and price moves through, the orders that held the level are gone, so the move can speed up for a while. What a wall does not do is just as clear. It promises no direction, and being large is no guarantee it will stay to the end. Walls often appear at round numbers simply because many people choose the same number, not because anyone knows something. The size of a wall also only means something compared with the asset's normal trading value. A wall that is small relative to daily turnover is absorbed in minutes, and even a large one rarely holds for long on a day when the whole market leans one way.

Spoof orders and vanishing walls

The thing to be most careful about in the order book is orders that never intend to be filled. The typical case is spoofing: placing a large bid to make it look as if many people want to buy, then cancelling it as price approaches and selling on the other side. Another variant spreads small orders across many prices so they look like a thick layer. In stock markets this is punishable market manipulation, and Korean law also bans it in virtual asset markets, but telling intent from the screen alone is hard. In the opposite direction, some genuinely large orders show only part of their size and hide the rest, so you can see fills printing again and again at a price where the visible size is small. Signs that justify suspicion are roughly these: the wall disappears or steps back a level or two just before price reaches it; the wall appears and vanishes every few seconds; there is large resting size but almost no fills at that price. When you see this, leave the wall out of your judgment and rely on actual fills and closed candles instead.

Common misconceptions

First, the idea that price rises when bid size exceeds ask size. Large size means many people are waiting at those prices, not that many are rushing to buy now. What actually moves price is not the resting limit orders but the market orders that hit them, so thick bids may simply be orders waiting for price to come lower. Second, judging pressure from the depth ratio alone. As shown above, the number can flip depending on how many levels you include, and a single large order can drag the whole ratio. Third, assuming what you see is everything. There are orders beyond the visible levels, and the same coin can have a completely different book on another exchange or in the futures market. Fourth, hoping that staring at the book long enough will let you call the next move. The book changes every second; following it by eye makes you react to every small change, and the flicker on the screen often ends up steering decisions more than the plan you made on the chart.

What looks different in crypto and stocks

In crypto each exchange has its own book, so the same coin shows different size and spread on Binance, Upbit and Bithumb, and automated quoting orders are packed so densely that size changes several times a second. Trading runs 24 hours, so in quiet late-night hours the book thins out and even small orders leave long wicks. Korean stocks publish the exchange's book with 10 levels on each side on brokerage screens, and large caps such as Samsung Electronics and SK hynix carry thick size at every level, so the spread is usually a single tick. During the call auctions before the open and just before the close, only the expected price and size accumulate with no fills, so the book has to be read differently then. US stock orders are spread across many exchanges and off-exchange venues, and the free screens most individuals see often show little more than the best quotes. Index products and large tech stocks have very deep books, but the size on one screen can hardly be taken as representing all resting orders.

• Crypto: each exchange has its own book and size changes every second
• Crypto: in quiet hours the book thins and wicks get longer
• Korean stocks: 10 levels are public, and only expected prices build up during auctions
• US stocks: orders are scattered across venues, so one screen is not the whole

Reading it on a live chart

The rightmost candle on a live chart has not closed yet, and the order book is a snapshot of an even shorter moment. When you read them together, matching time spans matters. If you are watching an hourly support line and change your mind because of a few seconds of book activity, information from different timeframes gets mixed and your reference wobbles. A forming candle that pokes below support and bounces off a thick bid is also not confirmed until the candle closes; if that bid is pulled just before the close, the candle can still close below support. Check the screen's refresh rate as well. When data arrives like this site's order book dashboard, every second for 20 levels and every ten seconds for 500 levels, the deep side of the picture can be up to ten seconds old. Treat what you see in the book as a hypothesis until a closed candle confirms it, and get used to watching how size changes over several seconds; that habit reduces the chance of being fooled by a single snapshot.

A practical checklist

The order book misleads least when used as a supporting tool to check ideas formed on the chart. Going through it in this order reduces the pull of the flickering screen. If anything looks odd at any step, give less weight to what you read from the book.

• Mark support, resistance and volume-zone prices on the chart first
• Check that the spread % is at its usual level
• Read the depth ratio together with how many levels it covers
• See whether thick size near the marked prices stays for more than a few seconds
• Use the trade list to confirm that fills actually print when price arrives
• Confirm the judgment again on a closed candle

Limits and disclaimer

The order book shows only part of the resting orders you can see right now, and those orders can be cancelled or hidden at any time before they are filled. The same asset has different books on different exchanges and markets, and the same moment looks different depending on refresh rate and the number of levels shown. Resting size and wall size do not tell you which way price will go, and using them alongside chart analysis guarantees nothing. The order book cannot replace fills and closed candles, which are the actual results of trading; it is closer to reference material kept beside them while interpreting. This article explains how the order book is built and how to read it, and it does not recommend buying or selling any asset. Trading decisions and their gains or losses are your own, and in leveraged trading, remember that losses can be larger than expected at moments when the book is thin.