Does a market order guarantee the price I see on screen?

No. A market order guarantees the trade fills, not the price. The number on screen is only a guide — the real fill can be a little worse because of slippage, especially for large orders or thinly traded coins.

When should I use a market order instead of a limit order?

Use a market order when getting the trade done quickly matters more than the exact price, and you're on a deep, high-liquidity pair where slippage is tiny. If you care about the exact price and can wait, a limit order lets you set the price instead.

Why did my market order fill at several different prices?

Your order ate through the cheapest offers first, and when those ran out it kept filling at the next-best prices. A big order on a thin market can sweep across several price levels, so the average fill price ends up worse than the top one you saw.

📖 Term 🟢 Plain English 🔰 Beginner

⚡ Market Order Market Order

An instruction to buy or sell right away at the best price currently on offer. It's the default order behind most exchange Buy/Sell buttons, and usually a beginner's first trade.

💡

Common misconception — Does a market order lock in the price you see? No! It guarantees the trade fills, but not the price. The real fill can be a bit worse than the screen number — that gap is called slippage.

⚡ A market buy starts at the 📖 cheapest sell offer and eats upward through the book — best price first, then the next-best, until it's filled. The more it has to climb, the worse your average price — that's slippage.

🛒 The simple version — "I'll take it at today's price"

Imagine walking up to a shop counter and saying, "I'll take it at whatever the price is right now." You're almost certain to walk out with the item, but you accept the current price tag instead of naming your own. A market order is that move on an exchange: speed and a near-certain fill, in exchange for giving up control over the exact price.

📖 How it actually fills

An exchange keeps an order book — a live list of standing buy and sell offers other people have parked. A market order matches against those resting offers: when you buy, it grabs the cheapest sell offers first; when you sell, it takes the highest buy offers first. If your order is bigger than the offers at the top, it keeps filling at the next-best prices, so one large order can fill across several price levels.

📊 Because a market order consumes offers that were already on the book, it's always a taker — it removes liquidity rather than adding it. A limit order is the one that can add an offer and wait.

⚖️ The trade-off: speed vs. price control

	👍 Good	👎 Watch out
⚡ Market order	Fast, near-certain fill	No price control; slippage risk
🎯 Limit order	You set the price (or better)	Might never fill

So the two are mirror images. A market order promises the trade happens but not at what price. A limit order promises the price but not that it happens.

🌊 Where slippage bites — and where it doesn't

Slippage is the gap between the price you expected and the price you actually got. Tap Buy expecting BTC at $100,000 and fill at $100,100, and that $100 is slippage. It's worst in fast-moving or low-liquidity markets, where few offers sit near the current price.

🐋 Deep pairs — Bitcoin and Ethereum on big exchanges have thick order books, so a normal market order fills with tiny slippage
🪶 Thin coins — a small-cap or barely-traded token has few nearby offers, so a market order can sweep several levels and fill at a noticeably worse price
📦 Big orders — the larger your order relative to what's resting on the book, the more price levels it eats through

❓ FAQ

Does a market order guarantee the price I see on screen?: No. A market order guarantees the trade fills, not the price. The number on screen is only a guide — the real fill can be a little worse because of slippage, especially for large orders or thinly traded coins.
When should I use a market order instead of a limit order?: Use a market order when getting the trade done quickly matters more than the exact price, and you're on a deep, high-liquidity pair where slippage is tiny. If you care about the exact price and can wait, a limit order lets you set the price instead.
Why did my market order fill at several different prices?: Your order ate through the cheapest offers first, and when those ran out it kept filling at the next-best prices. A big order on a thin market can sweep across several price levels, so the average fill price ends up worse than the top one you saw.

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