An order book shows offered prices and quantities, not a promise that they will remain when your order arrives. The best quote may cover little size, and displayed rows may be aggregated. Identify pair, side, units, grouping and time before estimating your quantity across relevant levels.
Assumes these offers remain available and are matched. It is not a live executable quote.
BTKWIN.COM · EDUCATIONAL EXAMPLEIdentify the two sides
Bids represent requests to buy, while asks represent offers to sell. In an ordinary ordered display, best bid is the highest buy price and best ask the lowest sell price. Last trade records a completed match instead of another current offered side.
Kraken’s pre-trade data documentation illustrates aggregated quantities at price levels. One row need not represent one person or one order.
Check the exact pair and product. A coin priced in a fiat currency has a different unit and venue book from the same coin against a stablecoin, and spot does not automatically share a derivative’s construction.
Best price may cover only part of the quantity
Suppose asks offer two units at 100 and five at 101 while a bid offers four at 99. To estimate buying three from the displayed sells, use two at 100 and one at 101. The bid at 99 is not quantity offered for you to buy.
The three-unit cost is 301 before fees, with average about 100.3333. Buying all seven displayed ask units costs 705, averaging about 100.7143.
These are calculations on a hypothetical static snapshot. They do not guarantee those offers persist, meet all venue rules or are matched when a real request arrives.
Separate level size from cumulative quantity
| Ask price | Level quantity | Cumulative quantity | Full level value |
|---|---|---|---|
| 100 | 2 | 2 | 200 |
| 101 | 5 | 7 | 505 |
Do not count cumulative liquidity twice
The second cumulative figure seven already includes the first two units. Adding two plus seven as independent sizes produces nine incorrectly. Likewise, a quote-currency value of 505 is not five base units and cannot be added to base quantity.
Read column labels and test the interpretation on two simple rows before estimating a larger trade. Different interfaces can display independent quantity, cumulative quantity or value instead.
A changed display grouping can alter bars and row count without introducing new orders. Compare like-for-like aggregation before interpreting visual differences as improved liquidity or a malfunction.
Grouping can hide price details inside a row
Some interfaces group nearby prices into ranges, while level-two feeds group orders at one exact price. Those are different levels of detail. Do not assume a grouped row’s label is the exact execution price for every unit inside it.
If comparing screens, align pair, data type, aggregation and time. A broad display can look simpler or deeper than a fine one without establishing a different economic condition.
Snapshots can also stop after a limited number of levels. Absence beyond the visible range is not proof that no other orders exist. Do not invent unlimited size at the last quoted price to fill the unobserved portion.
The trade tape answers another question
Trade history records what actually executed. The book records current offered liquidity under its source and conditions. A last-trade price can differ from both current best bid and ask.
If a buy limit is 100, five units offered at 101 are outside its price condition. Depending on instructions, some may fill within the limit while the remainder waits or ends. A candle touching a price does not establish complete matching for every order.
Our unfilled order guide explains the difference between price condition, size, priority and persistence. Use actual fills to account for a past trade rather than today’s changed book.
A visible wall is not a guaranteed forecast
A large level can be modified, cancelled or partially executed before your anticipated event. Its size alone does not prove one owner, intention or commitment to remain.
Historical volume is also different from depth currently available near your required prices. A busy market over a day can have limited quantity at the best level at the observed instant.
The calculation here explains potential execution structure, not a market-direction prediction or recommended entry. Accurate multiplication does not make future liquidity identical to the values entered.
Add fees after estimating the levels
The sum of quantity times price gives a pre-fee value under the snapshot assumptions. Account tier, pair, fill role and fee asset can change commission and net holdings. Inspect actual product rules.
A marketable limit order can take existing liquidity, while a resting portion can later add liquidity. The name Limit does not assign one fee category to every fill.
Our maker and taker guide shows the distinction. Do not combine spread, crossing multiple depth levels and commission into one unexplained difference.
Reconcile the actual result after execution
Preserve order ID, pair, side and associated fills. Sum actual quantities and values to calculate the weighted fill price, then add fees in their real units. Separate any unfilled remainder.
A prior book estimate can help explain a difference but cannot substitute for the record of what actually matched. Data changed between observation and execution is one possible explanation, not a conclusion to assume without evidence.
If the next goal is external receipt, inspect withdrawal and deposit conditions separately. A purchased service balance is not automatic delivery to your own wallet. Our help tool addresses that later stage.
A compact review before trusting the first number
Record venue, exact pair, product and time. Identify the opposite side for the intended action and distinguish level quantity from cumulative depth and quote value. Estimate the actual quantity across appropriate levels without double counting.
Then inspect instructions, available size and complete cost rather than treating one best quote as an all-size offer. Keep the assumptions explicit and avoid inferring the book owner’s identity or future behavior from a row.
The cost calculator can organize explicit amounts for a broader route. It does not supply a guaranteed execution price, inspect live depth or replace the final order preview.
Preserve the snapshot boundary
When sharing an estimate, say how many levels were visible and which quantity was evaluated. This makes clear where observed data ends and prevents another reader from extending the same average to a much larger order without evidence.
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English content and examples reviewed: 27 October 2026. Read the Arabic edition.
