A market order and a limit order answer two different questions. The market order says: fill me now, at whatever the other side is showing. The limit order says: fill me at 1.0850 or better, and if price never trades there, leave me out. Almost every other entry on the order ticket is one of those two instructions with a trigger condition bolted on the front.
Getting the choice wrong costs money quietly. A trader who uses market orders for everything pays the spread plus whatever moved between click and fill, several times a day. A trader who insists on limit orders for everything sits out the moves they read correctly, because price ran away from the level by two pips and never came back. Neither habit shows up as a single bad trade. Both show up in the monthly numbers.
Market orders: certain fill, uncertain price
A market order takes liquidity. It crosses the spread and matches against whatever is resting on the opposite side of the book. You buy at the ask and sell at the bid, which is why a fresh position shows a small loss the instant it opens. That is the spread, not a mistake in your entry.
On EURUSD during the London session, the difference between the price on screen and the price you receive is usually a fraction of a pip. During a central bank statement, the same order can fill several pips away, because the resting liquidity you aimed at was cancelled in the milliseconds before your instruction arrived. That gap is slippage, and it runs in both directions: sometimes you get a better price than the one you clicked. Brokers that quote symmetric slippage pass on both sides. Ones that only ever slip you negatively are worth questioning.
Limit orders: you set the price, the market decides if it agrees
A limit order rests in the book and waits. A buy limit sits below the current price, a sell limit above it. The order only executes at your price or better, which removes the risk of a surprise fill but adds the risk of no fill at all.
Limit orders are the natural tool for level-based entries. If your plan says buy the retest of a level at 1.0850, the limit does exactly that while you sleep. They also let you scale out: a sell limit above the market is simply a take profit for a long position, which is why platforms often label the same object differently depending on whether it opens or closes a trade. The mechanics do not change.
Stop orders trigger, they do not promise
A stop order is dormant until price touches its level, then it fires as a market order. A buy stop sits above the market and turns a rally into an entry. A sell stop sits below and does the same for a decline. This is how breakout traders enter and how almost every stop loss works.
The word "stop" causes more damage than any other term on the ticket. A stop loss does not guarantee your exit price. It guarantees that an order will be sent when the level trades. Over a weekend gap or through a sharp news candle, the fill can be far past the level, and the loss can be larger than the one you planned.
A stop-limit is the answer to that fear and comes with its own problem. It triggers at one price and then places a limit at another, so you cap the damage on the fill price but risk the position staying open while price keeps moving against you. For protective exits, most traders are better served by a plain stop plus smaller size. Cap the risk with position sizing, not with an order type that can refuse to close.
| Order | Where it sits | What it guarantees | Typical use |
|---|---|---|---|
| Market | Executes now | Fill, not price | Entry or exit when timing beats precision |
| Buy limit | Below market | Price, not fill | Buying a pullback into support |
| Sell limit | Above market | Price, not fill | Selling a rally, or taking profit on a long |
| Buy stop | Above market | Trigger only | Breakout entry, or covering a short |
| Sell stop | Below market | Trigger only | Breakdown entry, or a stop loss on a long |
| Stop-limit | Either side | Trigger plus price cap | Illiquid instruments where a market fill is unsafe |
| Trailing stop | Follows price | Trigger only | Letting a trend run without watching it |
The modifiers most traders never touch
Time in force decides how long a pending order lives. Good till cancelled leaves it in the book indefinitely, which is fine for a weekly level and dangerous for a setup based on this morning's range. Day orders expire at the platform's session rollover. Good till date lets you attach an expiry to the idea itself, so a stale order does not fire two weeks later into a market that has changed completely.
Immediate or cancel fills what it can right now and kills the rest. Fill or kill demands the whole size or nothing. Both matter once your order is large enough that the top of the book cannot absorb it in one go.
One cancels the other, usually written OCO, links two pending orders so that the execution of one removes the other. It is the standard way to bracket a range: a buy stop above, a sell stop below, and whichever side breaks first cancels the opposite. On a platform with proper order management, such as the pending order rail in eTrader, that pairing is visible on the chart rather than buried in a dialog, which makes it much harder to leave an orphan order behind.
Choosing, in practice
Use a market order when the cost of missing the trade is larger than a pip of slippage, and when the instrument is liquid enough that the two are not close. Use a limit order when you have a specific level and genuinely accept being left out. Use a stop entry when your thesis is that acceptance above a level confirms direction, and be honest that you are buying at a worse price in exchange for confirmation.
Trailing stops deserve one caution. They are excellent for trend positions you cannot watch and terrible in choppy conditions, where a fixed distance trail gets clipped by ordinary noise before the move develops. If you use one, set the distance from the instrument's typical range on your timeframe, not from a round number that feels comfortable. The same discipline applies to fixed exits, which is the argument made in more detail in the guides on stop loss placement and taking profit.
Trading leveraged products carries a high risk of loss, and no order type removes that. What order types do is make your intention explicit before emotion gets a vote, which is the only reason to learn them properly.
"Half the support tickets I have read about a bad fill were not bad fills. They were a stop order doing exactly what a stop order does, in a market that had no bids where the trader assumed there would be some."
— Alex Onta, Executive Director, SINGUARD
Key Takeaways
- A market order guarantees a fill but not a price; a limit order guarantees a price but not a fill.
- Limits rest against the market, stops rest with it: a buy limit is below price, a buy stop is above it.
- A stop loss fires a market order, so gaps and fast news can fill it well beyond your level.
- Time in force and OCO pairing prevent stale pending orders from firing into a market that has changed.
Frequently Asked Questions
What is the difference between a buy stop and a buy limit?
Both are pending buy orders, but they sit on opposite sides of the current price. A buy limit rests below the market and fills if price falls to it, so you are buying a dip. A buy stop rests above the market and triggers if price rises through it, so you are buying strength after a breakout. Placing one where you meant the other is a common and costly mistake.
Does a stop loss guarantee my exit price?
No. A standard stop loss is a trigger, not a price promise. When the market trades at your stop level the order becomes a market order and fills at the best available price, which in fast conditions or over a weekend gap can be well beyond the level you set. A stop-limit caps the fill price but can leave the position open if price runs past the limit.
Which order type should a beginner use?
Learn market orders and limit orders properly before touching anything else. Use a market order when being in the trade matters more than a fraction of a pip, and a limit order when you have a level you want and are willing to miss the move. Add stop and trailing orders once you can explain what each one does when price gaps through it.