Slippage
Difference between an expected trade price and the actual execution price.
Slippage is the difference between the price expected when a trade is submitted and the average price at which it actually executes. It can be negative, producing a worse result, or positive, producing a better one. Slippage is distinct from a stated trading fee, although both affect the final amount received.
In an order book, a market order may consume the best available price and continue through additional levels. A buyer expecting $10 based on the lowest ask might pay an average of $10.20 for a large order. In an automated market maker, the swap itself changes pool balances and the quoted rate. This expected movement from trade size is called price impact.
Slippage also occurs after the quote. Prices can move while an exchange processes an order or a blockchain transaction waits for inclusion. Other users may trade first, and searchers may reorder activity. Thin liquidity, high volatility, multi-hop routes, and slow confirmation increase uncertainty. Token transfer taxes or unusual contract behavior can reduce received amounts further.
The concept matters because paper prices do not guarantee executable value. A portfolio may show a new token worth thousands of dollars based on the last tiny trade, while selling the full holding would collapse its price. Traders should compare order size with cumulative market depth or pool liquidity, not only daily volume and the top quote.
Slippage tolerance is a related protection for swaps. It sets the worst acceptable output before the transaction reverts. A tight setting can cause failures and still consume gas. A loose setting can permit severe losses and create room for sandwich attacks. Limit orders provide a price boundary but may remain unfilled, partially fill, or behave differently across venues.
To reduce slippage, trade when liquidity is deep, use an appropriate order type, compare routes, and size positions around real exit capacity. Check spread, expected average fill, price impact, minimum received, and all fees. For large execution, specialized algorithms or professional services may help. Slippage is a measurable execution cost, and managing it requires realistic prices rather than assuming the screen's first quote applies to every unit.
Frequently asked questions
- Slippage occurs because quotes and available liquidity change before or while an order executes. Large orders consume several order-book levels or move an automated market maker's price. Volatility, network delay, other traders, transaction ordering, and token transfer fees can add further differences. Positive slippage improves execution, while negative slippage produces a worse result than expected.
- Trade smaller amounts in deep markets, use limit orders where supported, compare aggregator routes, and avoid unnecessary execution during extreme volatility. Review price impact, minimum received, fees, and real market depth. Splitting orders can help but adds fees and may reveal intent. Protected transaction submission can reduce some front-running risks, although every service introduces its own assumptions.
- It is possible when a limit order fills at its specified price or a small trade executes against abundant stable liquidity, but it should not be assumed. Even when a venue advertises zero slippage, cost may appear in the spread, fee, delayed execution, or provider's quote. Compare the final amount received with an independently observed executable price.