Slippage Tolerance
Maximum execution-price change accepted before a trade fails.
Slippage tolerance is the maximum unfavorable price change a trader agrees to accept between receiving a quote and executing a trade. In a token swap, the setting is commonly translated into a minimum amount received or maximum amount paid. If execution falls outside that boundary, the transaction should revert instead of completing at the worse price.
For example, a swap quote may offer 1,000 units and a one percent tolerance. The minimum received would be approximately 990 units, subject to how the interface calculates fees and routes. The setting does not predict actual slippage or guarantee a one percent loss. The trade may execute at the quote, somewhere inside the range, or fail.
Tolerance matters because blockchain prices can change while a transaction waits for inclusion. Other trades alter pool balances, and large orders create their own price impact. Volatility, thin liquidity, slow networks, multi-hop routes, and fee-on-transfer tokens can increase the required range. A setting that works for a deep stablecoin pool may be unsafe for a new token.
Setting tolerance too low causes repeated reverts, wasting network fees and time. Setting it too high gives the transaction permission to accept a much worse result. Searchers may use a visible trade to execute a sandwich strategy, buying before it and selling afterward while keeping the victim's output just inside the allowed minimum. High tolerance increases the room available for this extraction.
Some scam tokens fail sales unless users select extreme tolerance because hidden taxes or transfer rules reduce output. Raising the setting is not a reliable fix. Review contract code, expected taxes, liquidity, and actual sell behavior. Interfaces may offer automatic tolerance, but users should still inspect minimum received and understand whether it reflects price movement, fees, token mechanics, or all three.
Before confirming, compare expected and minimum output, price impact, route, network fee, and transaction deadline. Reduce trade size or use a deeper venue if acceptable execution requires a large range. Limit orders or protected transaction channels may provide better control. Slippage tolerance is a safety boundary, not an optimization target, and it should reflect the worst execution the trader can genuinely accept.
Frequently asked questions
- Use the smallest tolerance that is likely to execute under current liquidity, volatility, trade size, route, and network delay. Deep stable pairs may need little room, while thin tokens can require more. Do not copy a universal setting. Compare minimum received with your acceptable price, and reconsider the trade if execution requires a tolerance large enough to create a serious loss.
- A correctly implemented swap normally reverts when output would fall below the minimum accepted amount or input would exceed the maximum. The asset exchange does not complete, but the user may still pay network gas because validators executed the failing transaction. Deadline and tolerance checks depend on contract design, so use reputable interfaces and verify the confirmation details.
- Yes. Appropriate tolerance depends on pool depth, token taxes or transfer behavior, price volatility, trade size, route complexity, and expected inclusion time. A multi-hop trade can encounter movement at several stages. Some malicious tokens encourage extreme settings because ordinary sales fail. Raising tolerance blindly can expose users to sandwich attacks, poor pricing, or hidden token mechanics.