Slippage is the single most-asked question by DEX beginners, and the setting most likely to either cost you money or make your trades fail. Here's how to get it right.
What slippage is
Between the moment you see a quote and the moment your trade settles, the price can move — other trades hit the same pool, or the market shifts. Slippage is the difference between the price you expected and the price you actually got. It can land in your favor, but you plan for the times it doesn't.
Slippage tolerance: your safety limit
Your slippage tolerance tells the DEX the worst price you'll accept. If the market moves beyond it before settlement, the transaction reverts instead of filling at a bad price. In effect it's the gap between the quote and the minimum received shown in your wallet.
What to actually set
| Situation | Sensible tolerance |
|---|---|
| Large, liquid pairs (ETH, major stablecoins) | 0.1% – 0.5% |
| Smaller or more volatile tokens | 0.5% – 1% |
| Thin, fast-moving or brand-new tokens | 1% – 3%+, with caution |
Many interfaces offer an "auto" setting that adapts to the pair — a good default for beginners.
The two failure modes
- Set too low and trades fail repeatedly, because even normal movement breaches the limit. On Ethereum each failed attempt still costs gas.
- Set too high and you authorize a much worse price than expected — and you open the door to a sandwich attack, where a bot pushes the price right up to your tolerance, pockets the difference, and moves the market back.
The art is setting tolerance only as high as the pair's volatility genuinely requires — high enough to fill, low enough to stay protected. We separate slippage from its cousin, price impact, next.
- Cranking tolerance to 5–10% to force a stubborn trade through — an open invitation to sandwich bots.
- Setting it so low that liquid-pair trades fail and burn gas on every attempt.
- Confusing slippage tolerance (a market-movement buffer) with price impact (your own trade's effect).