Market vs limit orders: fills, price and slippage
The difference in one line: a market order guarantees you a fill but not the price, while a limit order guarantees the price but not the fill. A market order says “buy or sell now, at whatever the best available price is,” so it executes instantly but you might pay more than you expected. A limit order says “only trade at this price or better,” so you control the cost but the order may never fill. Everything else — slippage, maker and taker fees, stop orders — flows from that single trade-off between certainty of execution and control of price. This guide breaks it down with a comparison table and clear examples.
Last updated 21 June 2026 · by Mustafa Bilgic
The market order: certainty of execution
A market order is an instruction to buy or sell immediately at the best price currently available in the order book. It is the simplest order type and it does exactly one thing well: it gets you in or out now. The exchange matches your order against the resting orders on the other side, starting with the best price and working through the book until your full size is filled. The benefit is certainty — a market order in a liquid asset fills in milliseconds. The cost is that you accept whatever price the book gives you, and in a fast or thin market that can be noticeably worse than the price you saw when you clicked. Market orders are part of a broader family covered in order types explained.
The limit order: control of price
A limit order sets a boundary: the worst price you are willing to accept. A buy limit at $100 will only fill at $100 or lower; a sell limit at $100 will only fill at $100 or higher. If the market never reaches your price, the order simply waits in the book — or expires unfilled. This is the opposite trade-off from a market order: you get complete control over the price you pay, but no guarantee the trade ever happens. Limit orders are how you avoid overpaying, how you place entries at specific levels, and — because they rest in the book — how you often qualify for lower fees, which we cover below.
Side-by-side comparison
| Feature | Market order | Limit order |
|---|---|---|
| Guarantees a fill? | Yes (if liquidity exists) | No — only if price is reached |
| Guarantees a price? | No | Yes — your price or better |
| Speed | Immediate | Waits in the book |
| Slippage risk | Higher | None on the fill price |
| Typical exchange fee | Taker (higher) | Maker (lower) if it rests |
| Best when | You must get filled now | Price matters, you can wait |
Slippage on market orders
Slippage is the difference between the price you expected and the price you actually received. It is the hidden tax on market orders. Suppose the best offer for an asset is $100 but only for a small quantity; if your market buy is larger than that, it eats the $100 level, then $100.05, then $100.10, and your average fill ends up above the quote. In calm, deep markets slippage is tiny. In fast-moving or illiquid markets — exactly when you most want to trade quickly — it can be large. Automated systems are especially prone to underestimating it, which is why a backtest that ignores slippage can look great and lose money live. For depth, see slippage in trading bots.
Maker vs taker fees
Most exchanges, especially in crypto, price the two order types differently. An order that rests in the book and waits to be filled — a typical limit order — adds liquidity and is charged the lower maker fee. An order that fills immediately by removing existing liquidity — a market order, or a limit order that crosses the spread — is charged the higher taker fee. The gap is small on any single trade, but for an active strategy that trades hundreds of times it compounds into a real difference. This is one practical reason many automated strategies prefer limit orders: not only for price control, but to capture the maker fee. The flip side is that a resting limit order that never fills means a missed trade.
Stop orders, briefly
A third type worth knowing is the stop order, which is not an order type on its own so much as a trigger. A stop order sits dormant until the price hits a level you set, and then it becomes active — usually as a market order (a stop-market) or sometimes a limit order (a stop-limit). Traders use them to cap losses or protect profits without watching the screen. Be aware that a stop-market triggered in a fast move suffers the same slippage as any market order, so the price you exit at can be worse than your stop level. A stop-limit avoids that but risks not filling at all if price gaps straight through.
When to use each
The decision comes down to what you value more in the moment.
- Reach for a market order when execution certainty beats price: exiting a position in a fast move, cutting a loss, or trading a very liquid asset where slippage is negligible.
- Reach for a limit order when price control matters and you can afford to wait: entering at a specific level, trading something with a wide bid-ask spread, or wanting the lower maker fee.
For automated systems, the choice interacts with your whole approach — your risk-reward ratio, your position sizing, and how your backtest modelled fills. A strategy that assumed instant limit fills can fall apart live when those limits go unfilled, so test your assumptions honestly on the backtester and confirm them with paper trading before committing real capital.
Frequently asked questions
What is the difference between a market and a limit order?
A market order tells the exchange to buy or sell immediately at the best available price, so it guarantees a fill but not the price. A limit order sets the worst price you will accept and only fills at that price or better, so it guarantees the price but not the fill. Market orders prioritise certainty of execution; limit orders prioritise control of price.
What is slippage on a market order?
Slippage is the gap between the price you expected and the price your market order actually got. Because a market order takes whatever liquidity is available, it can fill across several price levels, especially in fast or thin markets, leaving you with a worse average price than the quote you saw. Slippage is one of the main hidden costs of trading and is often underestimated by automated systems.
What are maker and taker fees?
On many exchanges, a limit order that rests in the order book adds liquidity and pays a lower maker fee, while an order that fills immediately, such as a market order, removes liquidity and pays a higher taker fee. The difference is small per trade but adds up for active strategies, so favouring limit orders can meaningfully cut costs over time.
When should you use a market order versus a limit order?
Use a market order when getting filled right now matters more than the exact price, such as exiting a fast-moving position or trading a very liquid asset. Use a limit order when price control matters and you can wait, such as entering at a specific level or trading something with a wide spread. Many automated strategies use limit orders to control costs but accept that some will not fill.