How to Read Market Depth on a Crypto Order Book

Direct answer

To read market depth: find the midpoint between best bid and best ask, choose a price band (2% is a common default), then sum the quantity resting within that band on each side. Convert to quote-asset value so it is comparable across pairs. The result is the approximate size that can trade before moving the price beyond your band — which is your maximum sensible market order.

Step 1 — Identify the top of the book

Locate the best bid (highest buy price) and best ask (lowest sell price). Everything else is measured relative to these.

midpoint = (best ask + best bid) / 2

Step 2 — Choose a band

How far from the midpoint you are willing to see the price move. Common choices:

• ±0.5% — for size-sensitive execution.
• ±2% — a reasonable general-purpose default.
• ±5% — for judging whether a market exists at all on a thin pair.

Use the same band consistently, or your comparisons are meaningless.

Step 3 — Accumulate quantity within the band

Walk each side from the top outward, adding quantities until the price leaves your band.

Bid depth within 2% = 12,700 tokens. Repeat for the ask side.

Step 4 — Convert to quote-asset value

Token quantities are not comparable across pairs. Multiply by the midpoint:

12,700 tokens × 1.000 = 12,700 USDT of bid depth

Now "this pair has about 12,700 USDT of support within 2%" is a statement you can compare against any other market.

Step 5 — Check both sides

Measure the ask side too. The two are frequently unequal, and you need the side you will exit through as much as the side you enter through.

A book with 50,000 USDT of bids and 4,000 of asks is not a liquid market — it is a market where buying is expensive and where, if sentiment turns, the bids may not be there either.

Step 6 — Read the depth chart

Most interfaces plot cumulative depth as a stepped area chart: price on the horizontal axis, cumulative quantity vertical, bids extending left from the midpoint and asks right.

How to read the shape:

• Steep walls close to the midpoint — substantial depth nearby. Good.
• A flat stretch near the midpoint — little resting size close to the price. Orders will move the price immediately.
• A sudden vertical step — one very large order at a single price. Treat with suspicion; see Step 7.
• Asymmetric sides — more depth on one side than the other.

The chart is a visualisation of exactly what you computed in Steps 3–4. It is faster to read once you know what the numbers mean, and misleading if you read it without knowing.

Step 7 — Discount fake walls

A single enormous order can be placed to create an impression and cancelled before it is ever filled. Signals:

• Far larger than anything else on the book.
• Sitting at a round number.
• Retreating as the price approaches.
• Appearing and disappearing on a regular cadence.

The defence is not to detect every instance but to stop treating any single large order as information. Depth spread across many levels from many participants is meaningful; one enormous order is a claim.

A practical adjustment: recompute your depth excluding the largest single order. If the number collapses, the market's depth was that one order, and it may not be there when you need it.

Step 8 — Size your order

Now the measurement pays off:

Your maximum market order is the depth within the band you are willing to move the price.

Want to keep impact under 0.5%? Measure depth within 0.5% and do not exceed it. For anything larger, use limit orders or split across time — see how to reduce slippage.

Step 9 — Re-check before trading

Depth changes continuously and collapses fastest during volatility. A measurement taken minutes ago in different conditions is not the book you are about to trade against.

For anything significant, re-read immediately before submitting.

Common mistakes

• Reading only the top of the book. The best price applies to one small quantity.
• Measuring one side. You need the exit as much as the entry.
• Comparing depth in tokens rather than quote-asset value.
• Trusting a single wall.
• Measuring in calm conditions and trading in a fast market.
• Confusing the depth chart's smooth appearance with a smooth market. It plots resting orders, all of which can be cancelled.

Related

• Market Depth Guide — the concepts behind this routine.
• How to Measure Bid/Ask Spread — the other liquidity measure.
• Understanding Slippage — what happens when you exceed the depth.