Say a 0.5% slippage limit lets a wallet swap accept up to 0.5% less output than its quote; it is a cap, not a fee. For your first swap from a wallet, use the lowest setting that lets it complete, after checking the price impact, minimum received, and network fee.
What does the slippage setting control?
Slippage is the change between the amount shown in a quote and the amount your swap receives. The setting puts a limit on that change: your transaction will only complete if the final amount meets its minimum.
For example, if a quote offers 50 tokens for your USDC, a 0.5% limit sets the minimum near 49.75 tokens. Price impact is different: it is the effect your own trade has on the pool price, and it is already reflected in the quote. A wider limit does not undo that impact.
When checking a QuickSwap quote, look at the token pair and route; how developers connect QuickSwap swaps to pools explains why the route affects the quoted amount. Your wallet preview shows the result for this trade, including its minimum output.
What should you check before approving?
Compare the quoted output, minimum output, and price impact before confirming. If the minimum seems too low, try a smaller trade; a smaller order can move a pool price less. QuickSwap’s trade documentation describes how the minimum output is used during execution.
Also check the network fee, which pays for processing the transaction and is separate from the swap amount. Your wallet needs the network’s gas coin to pay it. The first swap of a token may also ask you to approve spending it; this permission can require a separate transaction and fee.
Keep approvals limited when the wallet offers that choice, and check the token name and address before signing. A familiar ticker alone does not prove a token is the one you intended.
What if the swap fails or the amount changes?
If the price moves beyond your limit before the transaction runs, the swap can fail instead of giving you less than the minimum. If the failed transaction was processed on-chain, you may still pay its network fee. Check its status on PolygonScan, a public Polygon block explorer.
Do not raise the limit automatically after a failure. First check whether the quote changed, the pool has enough liquidity, or the amount is too large. On QuickSwap, retry with a smaller amount or a refreshed quote; only widen the limit if you understand the lower minimum you are accepting.
- Check the pair, route, and quoted output.
- Set a low limit and note the minimum received.
- Keep enough gas coin for the swap and any approval.
- If it fails, check the transaction and refresh the quote before retrying.