Orders & execution · Intermediate

Understanding Slippage

The price on your screen is an indication, not a contract. Slippage is the gap between the two, and frequency is what makes it expensive.

Last reviewed 15 September 2026 by the MarketPro research desk · Editorial policy

In short

Slippage is the difference between the price you expected and the price your order actually filled at. It happens because the market moves between your order being sent and received, or because the size available at the best price is smaller than your order. It is worst around scheduled news, at session edges and across gaps, and it is worst of all on triggered stop orders.

What to remember

Slippage is a per-trade cost, so turnover multiplies it. The same 0.8 pips costs 16% a year at 200 trades and 3.2% at 40.
Triggered stops suffer most, because a stop becomes a market order exactly when price is moving decisively against you.
Positive slippage is real but not symmetric, because your market orders arrive disproportionately when price is already moving.
Log intended price against filled price. Within weeks you have a figure no broker's marketing page will give you.

Lesson 5 of 16 in Orders and execution

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What 0.8 pips of slippage costs across 200 trades

Slippage is the difference between the price you expected and the price you actually got. It is not an error and it is not your broker cheating you. It is what happens when the market moves in the interval between your order leaving and the market receiving it, or when the size available at the best price is smaller than your order.

The reason it deserves a lesson rather than a footnote is that it is a per-trade cost, so frequency multiplies it. Take a $10,000 account trading one standard lot, 200 round trips a year, with an average of 0.8 pips of adverse slippage across entries and exits. At $10 a pip that is $8 a trade and $1,600 a year, which is 16% of the account. A strategy that looked like it made 20% before costs made 4% after them.

Change one number and the picture changes completely. The same 0.8 pips across 40 trades a year is $320, or 3.2%. Slippage is not really a problem with execution, it is a problem with turnover, and it is the reason a scalping method needs a far larger raw edge than a swing method to arrive at the same result. The profit calculator makes the comparison on your own size.

Why the price moves between the click and the fill

Three mechanisms produce almost all of it.

Latency. Your order takes time to reach the venue. In a market ticking several times a second, the quote that was on your screen is already history by the time the order arrives.
Depth. The best price has a finite size behind it. If you buy more than that size, the remainder fills at the next price up, and the next, until the order is complete. The average fill is worse than the quote you saw.
Requoting and rejection. Some brokers hold the order briefly and offer you the new price rather than filling at the old one. That is not slippage in the strict sense, but it costs the same thing.

Stop orders are the most exposed of all, because a triggered stop is a market order that arrives precisely when price is moving decisively in one direction. That is the definition of a moment when the book is thin on the side you need.

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The three windows where it is worst

Scheduled releases. In the seconds around a payrolls or CPI print the EUR/USD spread can go from 1 pip to 10 or more and depth collapses. Slippage of 5 to 20 pips on a market order is ordinary there, not exceptional.
The session edges. At the Asian open, at the daily rollover and in the last hour before a weekend, there are simply fewer participants, so the same order moves price further. Our note on trading sessions maps when those windows fall in your time zone.
Gaps. A weekend gap or an equity opening auction skips a whole range of prices. Nothing traded in between, so nothing could have filled there, and a stop inside the gap fills at the other side of it.

Illiquid instruments carry all three effects permanently. An exotic pair or a small-cap stock has a wide quote and thin depth at all hours, so what is an event risk on EUR/USD is a baseline condition there.

Positive slippage is real and it is not symmetric

Fills can also come in better than requested. A buy limit filling below your price is the common case, and a market order occasionally catches a favourable tick. Any honest account of execution says this happens.

It happens less than the adverse kind for a structural reason rather than a conspiratorial one. Your market orders arrive disproportionately when price is moving, because that is when you decide to act, and a moving market is more likely to be moving away from you than towards you at the moment you chase it. Your stop orders are triggered by definition in the direction that hurts. So the distribution is skewed by which moments you transact in, not by the fills themselves. Expect roughly symmetric slippage on resting limit orders and asymmetric slippage on market and stop orders.

Measuring your own, broker by broker

Slippage is the one trading cost most people never measure, and it is straightforward to. Add two columns to your journal: intended price and filled price. The difference, in pips, logged for every trade, gives you a number within a few weeks that no marketing page will give you.

What to do with that number:

Build it into your expectancy. If your average slippage is 0.8 pips across the round trip, your strategy has to clear that 0.8 plus the spread before it earns anything.
Compare it by hour. If nearly all of it arrives in two hours of the day, the cheapest fix is to stop trading those two hours.
Compare brokers on it rather than on advertised spreads. Two accounts quoting the same 0.8 pips can differ by a full pip on fills, and that difference appears nowhere except in your own log.
Use limit orders where the setup allows, accepting that a limit trades slippage risk for the risk of not being filled at all.

The realistic expectation to carry into every trade is that the price on the screen is an indication, not a contract. Sizing so a poor fill is survivable is more useful than being surprised by one.

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Written and reviewed by the MarketPro research desk

MarketPro is a trading-signal and trading-education app operated by Harajuku Holdings LTD (Cyprus). Our signal desk publishes and tracks every trade idea in-app, and every page here is checked against the app's live behaviour before publishing. Last reviewed 15 September 2026. How we produce signals and content · About MarketPro

FAQ

Understanding Slippage: questions

What causes slippage in trading?

Three things, mostly. The market moves in the time your order takes to reach the venue; the size resting at the best price is smaller than your order, so the remainder fills at worse prices; and some brokers requote rather than fill at a stale price. All three get worse when volatility rises or when there are fewer participants, which is why news releases and session edges produce the largest gaps.

How can I reduce slippage?

Trade fewer times, trade in liquid hours, and use limit orders where your setup allows one. Avoiding the minutes around scheduled releases removes a disproportionate share of it for most strategies. A limit order caps the price you accept, though it trades the slippage risk for the risk of not being filled at all, so it is not a free improvement.

Is slippage always bad for the trader?

No. Fills can come in better than requested, and limit orders in particular fill at your price or better. The reason adverse slippage dominates for most people is that market and stop orders are sent at moments when price is already moving, and a stop is triggered by definition in the direction that hurts. Resting limit orders see roughly symmetric slippage.

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