Market orders, limit orders and stop orders

Start with the order book

On a centralised exchange, buyers and sellers place orders in an order book. The highest bid is the best price available to sell into, and the lowest ask is the best price available to buy from. Your order type decides whether you trade against that live book now or wait for the market to come to you.

The right order type depends on what matters more in that moment: certainty of execution, certainty of price, or a rule for getting in or out if the market reaches a level while you are not watching.

Market orders: execution first

A market order tells the exchange to buy or sell immediately using the best prices available. Suppose bitcoin is offered at $60,000 for 0.2 BTC, then $60,050 for the next 0.3 BTC. If you place a market buy for 0.4 BTC, the first 0.2 fills at $60,000 and the next 0.2 fills at $60,050. Your average entry is $60,025 before fees.

That is why market orders are best for very liquid pairs and modest size. You know the trade should happen now, but you do not know the exact final price in advance. On a thin market, the top of the book may contain very little size, so the later part of your order can execute much worse than the first part.

Limit orders: price first

A limit order sets the worst price you are willing to accept. Suppose ether is trading around $3,200 and you want to buy only if it dips to $3,100. You place a limit buy at $3,100. If the market trades down to that level, your order can fill there or lower. If the market never reaches $3,100, nothing happens.

Limit orders are useful when the spread is wide, when you are trading size, or when you want to avoid paying up in a sudden spike. The trade-off is that you might miss the move completely, or you might be only partly filled if there is not enough size at your level.

Stop orders: trigger first

A stop order becomes active only after the market reaches a trigger price. Traders often use a stop-loss to get out if the market moves against them. For example, imagine you bought SOL at $180 and want to cut the loss if it falls through $165. You set a stop at $165. If the market touches that level, the exchange activates the order.

Some platforms then send a market order, called a stop-market order. Others send a limit order, called a stop-limit order, where you also set the lowest sell price you will accept. A stop-market order is more likely to exit, but the price can jump in a fast drop. A stop-limit order protects the price more, but it can miss the exit altogether if the market gaps straight through your limit.

When each order type makes sense

• Use a market order when the pair is deep, the size is small and getting filled now matters more than shaving a few basis points off the price.
• Use a limit order when you care about entry or exit price, when the market is thin, or when you are placing an order away from the current market and are willing to wait.
• Use a stop order when you want a rule to act only after a level is reached, especially for risk control when you cannot watch the screen constantly.

Practical habits on thin markets

• Check the markets page first to see whether the coin trades actively at all.
• Compare the quote with convert so you know the reference price before you send a market order.
• Break a large order into smaller ones if the book is shallow.
• Remember that fees and spread still apply even if your order type is right.

Order types do not predict prices or remove risk. They are just tools for telling the exchange how to execute your decision.