Slippage changes the price you receive when your swap executes at a different rate from the quote shown before confirmation. It matters most when you trade a large order against a shallow pool or wait while the market moves.
Read these four figures before swapping
These figures separate the pool’s pricing from the protection you set in the interface.
- Quoted output: the amount of the ERC-20 token the pool estimates you will receive now.
- Minimum received: the lowest output your transaction accepts after applying your slippage tolerance. If execution would fall below it, the swap reverts.
- Price impact: the estimated movement caused by your own order changing the pool’s reserves.
- Fee: the portion of the input or output paid to liquidity providers, plus the separate network fee paid to process the transaction.
What actually moves the price
An Automated Market Maker prices your trade from its reserves, not from a fixed order book. In a simple constant-product pool, the reserve relationship is represented by x × y = k. Taking tokens out of one reserve makes the next units progressively more expensive.
Suppose a pool holds 100,000 USDC and 50 ETH. Before fees, a 1,000 USDC purchase returns about 0.495 ETH, even though the starting spot price is 2,000 USDC per ETH. The average execution price is roughly 2,020 USDC per ETH: the difference is price impact, created by your order.
The liquidity-provider fee reduces the output further and goes to the addresses supplying the pool. It is not slippage, even though both appear in the final result. A network fee goes to the chain’s transaction producers or sequencer. If the quoted pool price is stale, arbitrageurs trade against it and capture the discrepancy, so a delayed transaction can execute worse without your order being large.
How to choose a sensible tolerance
Set tolerance wide enough for normal movement but narrow enough to reject a bad fill. A 0.5% tolerance does not make the trade 0.5% more expensive; it permits execution up to 0.5% below the quoted output. It also does not guarantee that the quote itself is good.
Check whether a different pool or route has deeper liquidity. Multi-hop routes can improve the rate, but each hop can add a fee and another source of price impact. On Zero-Knowledge Rollups, cheaper execution can make smaller or split trades practical, but batching and proof generation do not remove the AMM curve.
If you need the broader SyncSwap context, follow the wider topic.
The practical rule is simple: compare quoted output with minimum received, then inspect price impact and fees separately. For a thin pool, reducing trade size or choosing deeper liquidity usually improves the price more reliably than merely increasing slippage tolerance.
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