Slippage tolerance sets a crypto swap’s lower limit

Slippage tolerance sets how much less a crypto swap may deliver than its quoted output before the transaction stops. A swap quote is a snapshot; by the time a transaction executes, pool prices or available liquidity may have changed.

The setting decides whether your swap completes at a worse price or reverts.

For a walkthrough of how a wallet swap handles a quote and token approval, the paraswap example shows where those steps sit. The tolerance itself is a limit on the final output, not a promise that you will receive the quoted amount.

What does slippage tolerance mean on a swap?

It is the maximum shortfall from the quoted output that you are willing to accept. If a swap quotes 100 units of a token and your tolerance is 1%, the transaction generally sets a minimum output of 99 units; if execution would produce less, it reverts.

This limit is usually expressed as a percentage, but the amount you should check is the minimum received shown in the swap details. That figure makes the trade-off concrete: a higher tolerance gives the transaction more room to complete, while accepting a lower possible return.

How is slippage different from price impact?

Price impact is the effect your own trade has on the pool’s price; slippage is the difference between the expected result and what the transaction can execute for later. A large order against a shallow pool can have high price impact before you submit it, even if the market does not move while the transaction is pending.

Tolerance does not reduce that initial price impact. It sets a boundary for how far execution can move from the quote, which may reflect both changing market conditions and the route’s liquidity. Review the quoted rate and price impact first; raising tolerance does not turn a poor quote into a good one.

How should a beginner choose a tolerance?

Start with the swap interface’s default or automatic setting, then inspect the minimum output before confirming. If a transaction fails, first check whether the quote has gone stale or the market moved; increasing tolerance should not be the first reflex.

• Compare the quoted output with the minimum output, not just the percentage.
• Consider the token pair and pool depth: thinly traded assets can move more during execution.
• If a swap keeps reverting, refresh the quote and review the route, size, and network conditions.
• Only raise tolerance when you understand why the trade needs more room and accept the lower minimum.

A tighter limit protects the price you accept but can make a swap revert when conditions shift. A looser one makes execution more likely, but can expose you to a worse fill; depending on the chain, a reverted on-chain transaction may still cost network fees.

Does a higher tolerance make a swap safer?

No: it relaxes the minimum-output check. A very high setting can allow a transaction to execute at a price far below the quote, so use the minimum received as your practical guardrail and avoid widening the limit just to force a trade through.

For most beginners, the sensible choice is the default setting unless the app explains why the route needs a change. If the minimum output looks unacceptable, wait for a fresh quote or reconsider the swap instead of agreeing to a worse floor.