Crypto Slippage FAQ — Why Your Order Filled at a Different Price

Why did my order fill at a different price than I saw?

Because a market order does not execute at one price. It consumes resting orders from the book, starting at the best available and walking deeper until your quantity is filled.

The price you saw was the best price for a specific — often small — quantity. If your order was larger than the amount resting there, the rest filled at worse prices, and your average is the blend.

Is slippage a fee charged by the exchange?

No. Slippage is a consequence of order-book depth, not a charge. Nobody receives it as revenue.

The exchange fee is separate and applied in addition. If you paid 1% slippage and a 0.2% taker fee, those are two distinct costs with two different causes.

How is slippage calculated?

slippage = (average fill price − expected price) / expected price

A buy expected at 100 that fills at an average of 101 shows 1% negative slippage.

For a buy, filling higher than expected is negative for you; for a sell, filling lower is negative. Both are "slippage."

What causes high slippage?

Three things, in order of weight:

Thin depth — few orders resting near the price. The dominant factor.
Order size relative to depth — not absolute size. The same order is trivial on one pair and catastrophic on another.
Volatility and timing — the book can change between submission and matching, and resting orders are cancelled and repriced continuously in fast markets.

How do I avoid slippage entirely?

Use a limit order. It refuses to execute beyond your specified price, so negative slippage becomes impossible.

The trade-off is that it may not fill, or may fill only partially. On an illiquid pair this asymmetry strongly favours limit orders: the downside of a limit order is not trading, while the downside of a market order is unbounded. Not trading is usually the cheaper failure.

What slippage tolerance should I set?

Derive it from the pair's actual depth rather than accepting a default.

Set too tight, orders fail repeatedly in normal conditions and each retry costs time during which the price moves. Set too loose, the setting stops protecting you — a 50% tolerance is a formality, not a safeguard.

A pair where 1% is routine needs a different setting from one that trades at 0.05%. Look at the book. See how to reduce slippage.

Can slippage work in my favour?

Yes. If the market moves your way between submission and execution, you can fill better than expected — a buy submitted expecting 100 that fills at 99.5 has positive slippage.

Venues differ in whether they pass this through. A system that gives you the worse price but keeps the better one is not passing through slippage; it is charging a spread.

Does splitting my order reduce slippage?

It can, if the book replenishes between pieces. You execute smaller portions, each within available depth, and let resting orders be replaced in between.

Two caveats. If the book is not replenishing, splitting just walks you down the same levels more slowly. And splitting introduces the risk that the market moves against you during execution — it converts a certain immediate cost into an uncertain spread-out one.

Why is slippage worse during big price moves?

Because depth is thinnest then. Market makers widen their quotes or withdraw when quoting becomes risky, so exactly when you most want to trade, there is least resting on the other side.

This is why slippage is worst during the moves that feel most urgent to act on.

How can I know my slippage before trading?

Read the book and walk it yourself. Accumulate quantity down the side you will hit until you reach your order size, and compute the weighted average price. Compare that to the top-of-book price.

This takes seconds and turns slippage from a surprise into a number you decided to accept. See how to read market depth.

I am a project — how do I reduce slippage for my holders?

Fund the order book. Slippage is a symptom of thin depth, so adding resting depth on both sides reduces it for every participant simultaneously.

No trading technique available to an individual holder fixes a book that has nothing in it. See how to plan launch liquidity.

Slippage — Frequently Asked Questions