Below graphs shows you the average and median slippage amounts observed in the past 3 months on Uniswap V3 network.

When placing limit orders, your trade will only get executed at or above the limit price. But with market orders, you buy at the price at which the market is willing to sell.

Slippage is the expected Percentage (%) difference between these quoted and executed prices. Low liquidity can also cause increased slippage, which is why larger orders tend to face higher slippage. When trading crypto, the volatility in asset price can create such a situation where the executed price is different from the quoted and expected price.