Setting Slippage for a BNB Token Swap

For a BNB token swap, set slippage to the smallest tolerance that lets a normal trade complete, because it caps how much less output you will accept than the quote. The swap screen estimates how many tokens you should receive. When you confirm, your wallet signs a transaction and sends it to the network. A validator includes it in a block, and the swap contract checks the pool’s current state and executes the trade.

That pool may have changed by the time the transaction runs. In a typical automated market maker, a trade changes the ratio of tokens held in the pool, which changes the exchange rate for later trades. The contract uses your slippage setting to calculate a minimum output. If the swap would return less than that minimum, it reverts instead of completing at the worse rate. Think of the setting as a lower limit on what you will accept, not a way to improve the quoted price.

A chart’s displayed price also does not tell you exactly what a swap of your size will return: the pool’s reserves and trade size affect the execution price. For more on that distinction, see this Poocoin explainer on how chart prices are formed.

What does slippage mean on a BNB swap?

Slippage is the difference between the expected output when you prepare a swap and the output available when the contract executes it. The tolerance sets the largest difference you will accept. A tighter setting means a higher minimum output, so the trade is more likely to revert if the pool price moves before execution. A looser setting makes execution more likely, but allows you to receive fewer tokens.

Slippage is not the same as price impact. Price impact is the change in the pool’s price caused by your trade, especially when the trade is large relative to the pool. Slippage also includes changes that happen while your transaction waits. A displayed quote may account for estimated price impact, while the tolerance covers how far the final result may fall below the quoted output.

How should you choose a slippage setting?

Start with the swap screen’s suggested setting, if it provides one, and check the minimum output before signing. Use these details to judge whether the setting fits:

• Trade size: A larger trade against a shallow pool can have more price impact. Consider splitting it if the quoted output is poor.
• Market movement: A fast-moving pool may change before your transaction is included. A very tight tolerance can cause repeated reverts.
• Token rules: Some token contracts deduct a transfer fee or impose other conditions. These can affect the received amount or make a swap fail; raising slippage may accept a worse result without fixing the underlying rule.

There is no single setting that suits every token and pool. For most swaps, prefer the lowest tolerance that allows the transaction to complete under current conditions. If the screen requires a much higher tolerance than expected, check the token, pool, and minimum output before proceeding.

What happens if slippage is too low or too high?

If slippage is too low, the contract’s minimum-output check can fail and the swap reverts. The trade does not complete, though the network may still charge a transaction fee for processing it. If slippage is too high, the swap can complete at a worse rate than the quote, up to the lower limit you accepted. Read that minimum-output figure before confirming: it translates the percentage into the amount of tokens you could actually receive.