What Is Slippage in Forex Trading?
A practical look at why forex orders sometimes fill at a different price than expected, and how execution quality varies between brokers.
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Slippage happens when a forex trade executes at a different price than the one you expected when you placed the order. It is a normal feature of how real markets work, not a sign that something has necessarily gone wrong — though the size and frequency of slippage can vary a lot between brokers and market conditions, which makes it worth understanding properly.
Why slippage happens
Prices move continuously, and there is a small amount of time between when you submit an order and when it actually reaches the market and gets filled. If the price has moved during that gap, even by a fraction of a second, your order fills at the new price rather than the one you saw on screen. The faster prices are moving, and the less liquidity there is behind a given price level, the more likely a meaningful amount of slippage becomes.
Positive and negative slippage
Slippage can work in either direction. Negative slippage means your order fills at a worse price than expected — you buy higher, or sell lower, than you intended. Positive slippage means it fills at a better price than expected. Both happen in genuinely fast-moving markets; a broker with fair execution practices should pass through both kinds as market conditions actually produce them, rather than only passing through the kind that happens to favor the broker.
When slippage is most likely
- Around major news releases, such as interest rate decisions, employment data, or surprise political announcements, when prices can move very quickly in a short window.
- During periods of thin liquidity, such as the very start of the trading week, around major holidays, or late in a session with few active participants.
- On larger order sizes, which can be harder to fill entirely at a single price when liquidity at that exact level is limited.
- With certain order types, since a market order — fill immediately at the best available price — is more exposed to slippage than a limit order, which fills only at your specified price or better, by design.
Slippage vs requotes
Slippage is sometimes confused with a requote, but they are handled differently. A requote happens when a broker cannot fill your order at the requested price at all and sends back a new price for you to accept or reject before the trade executes. Slippage, by contrast, fills the order automatically at whatever price the market has moved to, without asking first. Many modern brokers and order types are designed to fill with slippage rather than requote, since it generally gets the trade executed faster, though which approach a broker uses can affect how predictable your fills feel in fast-moving conditions.
Slippage and execution quality
How much slippage you actually experience depends heavily on your broker’s execution model and technology — how fast orders are processed, how deep the broker’s own liquidity is, and how transparently it reports fills. This is one of the less visible ways that two brokers advertising similar spreads can deliver a noticeably different real-world trading cost, since a wider spread with minimal slippage and a tighter spread with frequent negative slippage can end up costing a similar amount, or more, in practice. It is a detail worth factoring in alongside spreads and commissions when researching where to open an account — a broker finder can help you compare execution-related factors across regulated brokers rather than relying on headline pricing alone.
What you can actually control
You cannot eliminate slippage, since it is a feature of real markets moving in real time, not a flaw that can simply be engineered away. What you can do is be aware of when it is more likely to happen, such as around major news or thin liquidity, consider using limit orders when your exact entry price matters more to you than guaranteed execution speed, and factor typical slippage into how you judge a broker’s overall execution quality rather than judging a broker on spread alone.