Slippage
Slippage is the gap between the price you were shown and the price you actually got. It is usually small in busy markets and can be large in thin ones.
Photo: “Slippery When Wet Sign, Caution, Floor” by JeepersMedia, CC BY 2.0, via Flickr (edited: cropped and resized).
Slippage is the gap between the price you expect and the price your trade fills at. The SEC warns that with a market order, the price you pay may not be the one you expected [1]. On a DEX, larger trades move a pool’s price more [2].
Key points
- 1Slippage comes from two sources: the market moving before your trade fills, and your own trade moving the price.
- 2On a DEX, the part caused by your own trade is called price impact and grows with trade size.
- 3Front-running bots can add to your slippage by trading just before and after you.
- 4On Uniswap, a minimum amount out (amountOutMin) sets the worst result you will accept from a swap [3].
Why does slippage happen?#
On an order-book exchange, a market order buys or sells at the best prices currently available. The SEC notes that such an order is almost always executed when there are willing buyers and sellers, but that the price you pay may not be the one you expected [1]. A limit order, by contrast, executes only at the chosen price or better [4] — it avoids slippage but may not fill at all.
On a DEX that uses a pool, your trade itself shifts the ratio of the pool’s two tokens, so each extra unit costs a little more. Uniswap explains that larger trades relative to pool depth move the price more, while smaller trades execute closer to the current spot price [2], and that its AMM gives instant feedback on rates and slippage before you swap [5].
| Step | Value |
|---|---|
| Swap 1,000 USDC → average price | ≈ 3,019.03 (≈ 0.63% above quote) |
| Swap 10,000 USDC → average price | ≈ 3,109.03 (≈ 3.63% above quote) |
| Swap 30,000 USDC → average price | ≈ 3,309.03 (≈ 10.30% above quote) |
Computed with x × y = k, fee included. The fee is the same 0.30% each time; the rest of the gap is price impact, which grows with trade size. Deeper liquidity shrinks it.
How can slippage be made worse on purpose?#
Pending blockchain transactions are public before they are confirmed. ethereum.org describes sandwich trading: a bot spots a large pending DEX trade, buys just before it and sells just after it, and the user who is sandwiched faces increased slippage and worse execution [6]. Some venues cap slippage in their own tools; Hyperliquid, for example, documents a maximum slippage of 3% on each sub-order of its TWAP orders [4].
The main defence on a DEX is a limit you set yourself. Uniswap’s router asks for a safety parameter on every swap: the minimum amount received when you sell an exact amount (amountOutMin in the code), or the maximum amount you are willing to pay when you buy an exact amount [3]. Uniswap’s guide says this limit should come from a price source outside the pool and warns that, without one, trades can be front-run “for considerable loss” [3]. It adds that such attacks are mitigated by trading in extremely liquid pools and/or at low values [3].
Which words are related?#
- Liquidity — the main thing that keeps slippage small.
- Order books and liquidity — how slippage works on centralized exchanges.
- Mempool — where pending transactions wait, visible to front-running bots.
Frequently asked questions#
Is slippage always bad?
No. If the market moves in your favour between quote and execution, you can get a better price. Price impact from your own trade, however, always works against you.
Does routing through several pools increase slippage?
It can. The Uniswap v2 whitepaper notes that when trades had to pass through an ETH pair on both sides, traders paid fees twice and suffered slippage twice [7].
Is slippage the same as a fee?
No. A fee is a fixed charge, such as 0.30% per swap in Uniswap v2 [7]. Slippage depends on trade size, liquidity and market movement.
What is amountOutMin?
It is the name of the minimum-amount-received parameter in Uniswap’s router code. Uniswap’s example notes that amountOutMin “must be retrieved from an oracle of some kind” — a price source outside the pool [3].
Sources#
Grade A = primary source (regulator, protocol specification, client code, original author). Grade B = expert secondary source used for explanation only.
- AU.S. Securities and Exchange Commission — Investor.gov. Market Order, 2026.
- AUniswap Labs (developer documentation). How Uniswap Works, 2026.
- AUniswap Labs (developer documentation). Implement a Swap (Uniswap v2 guide), 2026.
- AHyperliquid Docs. Order types, 2026.
- AUniswap Labs (developer documentation). Uniswap v2 Swaps, 2026.
- Aethereum.org. Maximal extractable value (MEV), 2026.
- AHayden Adams, Noah Zinsmeister, Dan Robinson. Uniswap v2 Core (whitepaper), 2020.