What is slippage in crypto?
The price on screen is a quote, not a promise. Between clicking swap and the trade landing, two things can move it.
On this page
Slippage is the difference between the price you expect for a trade and the price it actually executes at. On decentralized exchanges it comes from your own trade moving the pool's price (price impact) and other trades landing first. A slippage tolerance caps how much worse you will accept.
What is the difference between slippage and price impact?
Uniswap's documentation separates the two. Price impact is built into automated market makers: as your swap executes, it shifts the ratio of the two assets in the pool, so each extra unit costs more. The more liquidity in the pool, the smaller the impact for a given trade size. Slippage, in Uniswap's wording, is the price change that can happen while your submitted transaction is still pending, because other swaps may be processed before it.
| Price impact | Slippage | |
|---|---|---|
| Caused by | Your own trade's size relative to the pool | Other trades executing before yours |
| Known before you click? | Yes, the interface estimates it | No, it depends on what happens next |
| Reduced by | Deeper pools or smaller trades | A tight tolerance (at the cost of failed swaps) |
Centralized exchanges have the same issue: Investor.gov notes that with a market order the price you pay may not be the price you expected.
How big can price impact get?
Uniswap v2 pools follow the constant-product rule x × y = k and charge a 0.30% fee, so larger trades relative to the pool get worse rates. How decentralized exchanges price trades is covered in how decentralized exchanges work.
How does slippage tolerance protect a trade?
Before you swap, you set how much extra movement you will accept, for example 1%. Uniswap's docs say that if the final price falls outside that margin, the transaction fails and the swap does not happen. In the example above, a 1% tolerance would set a minimum of about 4.70 ETH; anything less and the trade reverts. A failed swap can still cost network fees — see gas fee.
- Mistake: setting tolerance very high to make a swap go through. You are agreeing in advance to a much worse price.
- Mistake: trading size into a thin pool. Check the estimated price impact first; see market liquidity explained.
Questions readers ask
Can slippage ever be positive?
Yes. If the price moves in your favour while the transaction is pending, you can receive more than the quote. Tolerance settings only limit the downside.
Is slippage the same as the bid-ask spread?
No. The spread is the gap between buy and sell quotes at one moment; slippage is the gap between your expected and actual execution price. Both are trading costs — see bid-ask spread.
On a decentralized exchange, the price you see assumes your trade has no effect and nothing changes before it lands. Check price impact, keep tolerance tight, and remember that pool depth matters as much as price. Liquidity pools themselves are covered in liquidity pools and impermanent loss.
Sources
- Uniswap documentation, Swaps (protocol concepts) (2026)Primary source
- Uniswap documentation, How Uniswap works (v2 protocol overview) (2026)Primary source
- Investor.gov, US Securities and Exchange Commission, Market order (glossary) (2026)Primary source
Educational content only — not financial, investment, legal or tax advice. Crypto-assets are high-risk and you could lose all the money you put in. Rules differ by country; check with your national regulator. See our risk disclosure and editorial policy.
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