What does slippage tolerance mean in a swap and how does it affect what I receive

05 September 2026

Slippage tolerance is the maximum percentage difference you accept between the quoted price of a swap and the price at which the swap actually executes. If the market moves against you by more than that percentage, the swap will fail instead of completing at a worse rate.

The core idea is simple: a swap quote is a snapshot of one moment. Between the time you see the quote and the time your transaction is confirmed on the blockchain, the price of the tokens can change. Slippage tolerance is your guardrail against that change.

How slippage happens

Liquidity on decentralized exchanges comes from pools of tokens. When you swap, you are trading against one of those pools. The more you trade relative to the pool's size, the more the price moves against you. That is called price impact. Slippage is the additional movement caused by other traders and the time delay.

Consider a scenario. You see a quote for 1 ETH at 3,000 USDC. You approve the swap. Someone else swaps a large amount of ETH for USDC in the same pool before your transaction lands. The pool's price shifts. Your swap now executes at 2,990 USDC instead of 3,000. That 10 USDC difference is slippage.

Setting your tolerance

The exchanger you use will offer a default slippage tolerance, often 0.5% or 1%. You can adjust it.

A low tolerance, say 0.1%, protects you from large price moves. If the price shifts more than 0.1%, your swap fails. You lose nothing except the network fee for the failed transaction. This is useful when trading stablecoins or tokens with deep liquidity, where price moves are small.

A high tolerance, say 5% or 10%, allows the swap to go through even if the price moves significantly. This is riskier. You might receive far fewer tokens than you expected. High tolerance is sometimes used for trades involving illiquid tokens, where even a small trade causes large price impact. But it can also be used by malicious actors to front-run you. If you set a very high tolerance, a bot can see your pending transaction and push the price against you, capturing the difference.

What you actually receive

The amount you receive is determined by the execution price, not the quoted price. The execution price is the price at the moment your transaction is included in a block. Slippage tolerance sets a boundary: the execution price must be within that percentage of the quoted price. If it is, the swap proceeds and you get whatever the market gives at that moment. If it is not, the swap reverts.

The relationship is direct. A wider tolerance means you accept the possibility of receiving less. A narrower tolerance means you accept the possibility of the swap failing.

Slippage vs. spread

Slippage is not the same as the spread. The spread is the built-in difference between the buy and sell price of a token on the exchange. You pay that regardless of timing. Slippage is the extra cost from market movement during the delay. The hub page "What a crypto swap actually costs" explains how spread, network fees, and slippage combine to produce the total cost of a swap. That page is worth reading after you understand slippage, because it shows you where each part of the cost comes from.

Practical note

Most swaps on decentralized exchanges fail because of slippage, not because of a bad quote. If you are swapping a token with low liquidity, consider setting a slightly higher tolerance, but check the price impact first. If the price impact is already high, a higher tolerance only adds more risk. The safest approach is to use the default tolerance and let the swap fail if the market moves. Then try again. You lose a small network fee but avoid a bad trade.

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