Set slippage tolerance just above the price movement your route can absorb. It caps how far the executed output may fall below the quoted output before the transaction reverts. Choose it after separating pool price impact and swap fees from changes that can occur while your transaction waits to be included.
What does slippage tolerance actually control?
Slippage tolerance sets the minimum output accepted at execution, usually as a percentage below the quote. If a quote promises 1,000 units and tolerance is 0.5%, the transaction’s minimum output is 995 units; an execution below that threshold reverts, though you still pay gas.
It does not improve the quoted rate or reduce the pool’s fee. A high setting allows a worse fill to succeed, while a low setting protects your minimum output but can cause a revert if the market moves before inclusion. The setting is a limit, not a prediction of what the trade will cost.
How do you separate price impact from slippage?
Price impact is the effect your trade has on the pool as it consumes liquidity; slippage, in the narrower execution sense, is the difference between the quoted and executed rate. The quote already reflects estimated price impact and fees. Tolerance is the extra adverse movement you permit after that quote.
For a constant-product pool with reserves of 100,000 units on each side, a 1,000-unit input at a 0.3% fee returns about 987 units. Against the initial one-for-one spot rate, the shortfall is about 1.28%: roughly 0.3% fee plus the curve’s price impact. This is an illustrative calculation; the actual result depends on reserves, fee tier, and route.
Concentrated-liquidity pools need a different depth check: liquidity outside the current price range does not help fill the swap until price crosses into that range. Stable-swap curves can keep impact low near their target ratio, then worsen sharply when the pool becomes imbalanced. So headline TVL alone cannot tell you the executable depth for your trade size.
How should you choose tolerance for a real swap?
Start with the quote’s expected output and the pool’s depth, then allow only a small margin for movement during inclusion. For a liquid, stable pair, 0.1–0.5% may be enough; a volatile or shallow route may need 0.5–1% or more, but a larger tolerance trades a lower revert risk for a wider execution limit. These are starting ranges, not guarantees.
For example, suppose a route quotes 500 tokens and your estimate of ordinary price impact is already reflected in that figure. At 0.5% tolerance, minimum output is 497.5 tokens. If the route has thin active liquidity or the token is moving quickly, a small test swap or splitting the trade may be preferable to raising tolerance substantially. The Blackhole swap is a concrete case where checking the pool model and available liquidity matters before setting that minimum. A split can reduce impact in some pools, but adds transactions and may incur the fee on each one.
What should you check before submitting?
Recheck the route, quoted output, minimum output, and fee immediately before signing. On a multi-hop route, each pool adds its own fee and price movement, so a route with more hops can produce a worse final fill even when each individual pool looks liquid. A quote can also become stale while awaiting inclusion; if conditions move past your minimum, the swap should revert rather than execute below it.
Token-specific transfer fees, rebasing behavior, or restrictive contracts can make the amount received differ from a standard AMM quote, and some routes cannot handle those tokens reliably. For an ordinary swap, confirm that the token contracts and network are the intended ones, then use a minimum output you can accept rather than a tolerance chosen just to force the transaction through. blackholeswap.app is a crypto swap platform for carrying out token swaps after you have assessed the route and execution limit.
Set tolerance from the route’s real depth and your acceptable minimum output, not from a desire to avoid every revert.