Every order is a trade-off between two things you cannot have at once: certainty of execution and certainty of price. Choose the wrong one for the situation and you either miss the trade entirely or get filled somewhere you never intended.
Market orders — certain fill, uncertain price
A market order says: fill me now, at whatever is available. It will execute (in any normal market), but the price is whatever the book offers at that instant.
Use it when being in the trade matters more than the exact level — exiting a losing position, or entering a move already underway. Avoid it in the seconds around a data release, where "whatever is available" can be a long way from what you saw.
Limit orders — certain price, uncertain fill
A limit order says: fill me at this price or better, and not otherwise.
- Buy limit sits below the current price — you are waiting for a dip.
- Sell limit sits above it — you are waiting for a rally to fade.
You control the price exactly. What you do not control is whether it ever trades. A limit one pip below the low of the move is not a clever entry; it is a missed trade with a good story attached.
Stop orders — the opposite logic
A stop order triggers once price reaches a level, then becomes a market order. It is used to enter in the direction of a move, or to exit a losing one.
- Buy stop sits above the current price — you want in if it breaks higher.
- Sell stop sits below — you want in if it breaks lower, or out if you are long.
The essential point, and the one that catches people: a stop is not a guaranteed price. It is a trigger. Once touched, it becomes a market order and fills at the next available price. In a gap or a spike, that can be materially worse than the level you set. Your stop defines where you intend to exit, not the worst you can do.
Some brokers offer a guaranteed stop that does fill at your level regardless of gaps, usually for a fee or a wider spread. That is the only version that caps risk absolutely.
Getting the direction right
Limit and stop orders sit on opposite sides of price for the same action, which is where most confusion lives. The rule:
- Buying below the market → buy limit. Buying above → buy stop.
- Selling above the market → sell limit. Selling below → sell stop.
Limits are for better prices; stops are for confirmation. Mixing them up places your order on the wrong side and it fills instantly at the market, or never.
Take profit and trailing stops
A take profit is a limit order on the exit side — it closes the position at a target you set in advance. Its value is not the price; it is that the decision was made before you had money riding on it.
A trailing stop follows price by a fixed distance as the trade moves in your favour, and stays put when it moves against you. It locks in gains without requiring you to watch. The trade-off is that a trail tight enough to protect much profit is also tight enough to be clipped by ordinary noise. On a pair covering 80 pips a day, a 15-pip trail will exit most trades early.
Order duration, and OCO
Pending orders need a lifetime. GTC (good till cancelled) sits until filled or removed — check it periodically, because an order placed for a setup that expired days ago can fire into a completely different market. Day or GTD orders expire on their own, which is usually what you actually want.
OCO — one cancels the other — pairs two orders so that filling one removes the other. It is how a stop loss and take profit coexist on the same position without leaving a stray order behind once the trade closes.
What to take from this
- Market orders guarantee a fill, not a price. Limits guarantee a price, not a fill.
- Stops are triggers that become market orders — they can and do slip.
- Limits sit where price is better; stops sit where price is confirmed.
- A trailing stop tight enough to protect a lot is tight enough to exit early.
- Give pending orders an expiry, and use OCO so exits clean up after themselves.
Next: leverage and margin — the mechanism that makes small accounts viable and, handled carelessly, ends them fastest.