Set slippage tolerance by checking the quoted output, estimating how much it could move before your transaction executes, and choosing the smallest tolerance that still gives it a reasonable chance to complete. On Avalanche C-Chain, this setting defines a minimum output for the swap; it does not lock in a price.
What does slippage tolerance actually limit?
Slippage tolerance is the amount your received tokens may fall below the quoted amount before the swap reverts. A decentralized exchange typically turns it into a minimum-output condition in the transaction: if the swap would return less, the contract rejects it.
That limit addresses changes between the quote and execution. A transaction waits to be included in a block, and other swaps can change the pool’s reserves in the meantime. Your trade can also move the price itself; that effect is called price impact. The quote may already reflect expected price impact, while slippage tolerance covers a further change before execution.
For example, suppose a swap quotes 100 USDC for 1.80 AVAX and the tolerance is 1%. If the interface applies that percentage to the quoted output, the minimum is 1.782 AVAX. A transaction that would return less should revert. The percentage is not a discount or an extra fee, and the result can differ if the interface calculates its minimum another way.
How do you choose a setting and check the result?
Start with the quote and the pool conditions, then choose a tolerance that fits the likely movement during execution. A deep pool and a small trade usually have less price impact than a shallow pool or a large trade. Volatile markets and a congested network can also leave more time for the quote to change. A wider tolerance may help a transaction complete, but it accepts a worse minimum output.
Imagine swapping 100 USDC for AVAX through an Avalanche C-Chain pool. If the quote is 1.80 AVAX and your chosen 1% tolerance sets a 1.782 AVAX minimum, compare that floor with the amount you would still accept. If the pool is thin or the market is moving quickly, check the quote again before confirming; don’t raise the tolerance automatically just to clear a failed swap.
Before signing, confirm the token pair, quoted output, minimum output, and network in your wallet. A wallet connected through WalletConnect still asks you to approve the transaction yourself. After submission, the swap either executes at or above its minimum or reverts; a reverted on-chain transaction can still consume network gas, usually paid in AVAX.
Does a lower tolerance always save money?
No. A lower tolerance caps how far below the quote the output may fall, but it can make a transaction revert when the pool changes slightly before execution. You may then need to submit again, which can mean paying gas again. Choose a floor you can accept and a tolerance that reflects the pool and market, rather than treating the lowest setting as automatically best.
Where does Blackhole swap fit into this?
When swapping or exploring liquidity on Avalanche C-Chain, the same checks help you understand the trade before you approve it. The Blackhole swap service is one way to make those swaps or provide liquidity. Whichever pool you use, decide whether the minimum output is acceptable before signing; that is the protection the tolerance setting gives you.