Buy Order Definition in Crypto

A buy order is an instruction to purchase a specific amount of an asset on an exchange under set conditions. In crypto trading, it records a trader’s intent to acquire a coin or token and sits alongside other orders in the market’s order book.

How a buy order moves through an exchange

When you submit a buy order, the exchange’s matching engine looks for one or more sell orders to satisfy it. If your price meets the available asks, the trade executes. The exchange facilitates the match between buyers and sellers rather than selling to you itself.

Market buy order

A market buy tells the exchange to buy right now at the best price available. It favors speed over price control, which makes it useful when you want quick entry and are comfortable with the trade executing at the current market price.

Liquidity, slippage, and partial fills

Market buys are filled against the limit sell orders already in the order book. If the cheapest ask cannot fill your entire order, the system continues up the book until the quantity is met. This sweep can produce slippage, where your average fill price ends up higher than the first quoted price.

Limit buy order

A limit buy sets the maximum price you are willing to pay. The order only executes at your limit price or lower, which gives control over the execution price but does not guarantee a fill if the market never trades at your level. 

Fees and trade-offs

Because market orders execute immediately against existing orders, they are treated as taker trades on many exchanges. That structure can result in higher fees compared with orders that add liquidity, and combined with slippage it can make fast entries more expensive than planned.

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