Slippage is one of the most misunderstood costs in retail trading — understanding exactly how it works can change how you place every order.
You click "Buy" on EURUSD at 1.0850. Your trade confirms at 1.0853. Three pips vanished before you even had a position. That gap has a name — slippage — and it is not a glitch, a fee, or a mistake. It is a structural feature of how electronic markets work, and every trader encounters it eventually.
Slippage Is the Distance Between the Price You Expect and the Price You Get
When you submit a market order, you are asking to be filled at the best available price right now. The problem is that "right now" is not frozen. In the time between your order leaving your device and the execution engine processing it — even if that interval is measured in milliseconds — the market can move.
The difference between your expected price and your actual fill price is slippage. It can be positive or negative:
- Negative slippage — you buy higher than quoted, or sell lower than quoted. This increases your cost.
- Positive slippage — you buy lower than quoted, or sell higher than quoted. This works in your favour.
Brokers that run an STP (Straight-Through Processing) or A-Book model pass your order on to their liquidity providers. That means your fill depends on what price is genuinely available at the moment of execution — not a price that was displayed half a second earlier.
Three Conditions That Make Slippage More Likely
Slippage is not random. Certain market conditions reliably increase its frequency and magnitude.
1. Low liquidity periods Liquidity describes how much volume is available at any given price level. During off-hours — the gap between the New York close and the Tokyo open, for example — fewer participants are quoting prices. The spread widens, and even a modest order can push through the top of the book to a worse level.
2. High-impact news releases When a scheduled data release hits — such as the Canadian CPI figures due Monday at 08:30 ET, or US Retail Sales on Tuesday — prices can reprice by several pips in under a second. Orders queued just before the print may fill at a materially different level than the pre-release quote.
3. Large order size relative to available depth If you are trading a standard lot (100,000 units) in a thinly traded instrument, your order may consume the entire volume available at the best price and spill into the next price tier. The average fill across all those tiers is worse than the top-of-book quote you saw.
A Worked Example: How Slippage Accumulates in Practice
The following numbers are for illustration only and do not represent live market prices or guaranteed outcomes.
Suppose GBPUSD is quoted at 1.2700 bid / 1.2702 ask. You place a market buy order for two standard lots (200,000 units) one second before a major UK CPI release.
At the moment your order reaches the execution engine, the release has printed. The available depth looks like this:
| Price Level | Volume Available |
|---|---|
| 1.2702 | 80,000 units |
| 1.2705 | 70,000 units |
| 1.2709 | 50,000 units+ |
Your 200,000-unit order fills across all three levels. The blended average fill price works out to roughly 1.2705 — five pips above the ask you saw before clicking. On two standard lots, each pip is worth approximately $20 (illustrative), so that five-pip slippage costs around $100 on entry alone, before the spread is even counted.
This is why experienced traders often reduce their position size around scheduled events, or use limit orders instead of market orders when entering during volatile windows.
Limit Orders: The Primary Tool for Controlling Slippage
A limit order specifies the maximum price you are willing to pay (for a buy) or the minimum price you will accept (for a sell). If the market cannot fill you at that price or better, the order simply does not execute.
This eliminates negative slippage on entry — but it introduces a different risk: non-execution. If price moves away from your limit before the order fills, you miss the trade entirely.
The practical trade-off:
- Market orders — guaranteed execution, uncertain price.
- Limit orders — certain price, uncertain execution.
Neither is universally superior. The right choice depends on whether you need to be in the trade at any cost, or whether the specific entry price is critical to your risk-reward calculation.
Stop-loss orders, which are also used for risk management, carry their own slippage risk: in fast markets, a stop may trigger but fill several pips beyond the stop level. This is called stop slippage and is distinct from entry slippage — both matter when you are calculating your actual risk per trade.
One Actionable Takeaway
Before placing any market order, check the economic calendar for releases in the next few minutes. If a high-importance event is imminent — like a central bank statement or a tier-one data print — consider waiting for the initial volatility to settle, or switch to a limit order with a price you are genuinely comfortable being filled at. Slippage cannot always be avoided, but it can almost always be anticipated.
For information only. This is market commentary and education, not investment advice. Figures are as at the time of writing.