A swap preview can already reflect the effect of your trade size before the market changes again. Price impact and slippage therefore require separate reference points. This guide follows an illustrative liquidity-pool calculation, then checks expected output, minimum receipt and fees without treating every difference as one deduction.
Slippage compares an execution result with a stated reference. To measure it usefully, record the direction, quantity, time and fee treatment before calculating a percentage. These worked examples use hypothetical prices to distinguish the average execution price from the total cost and from a swap’s minimum acceptable output.
The bid-ask spread helps explain why immediately buying and selling can return less even without a change in the best quotes. Use two prices, a defined quantity and time, then add fees separately. The examples below are hypothetical arithmetic, not current prices or an invitation to trade.
An order book shows offered prices and quantities, not a promise that they will remain when your order arrives. The best quote may cover little size, and displayed rows may be aggregated. Identify pair, side, units, grouping and time before estimating your quantity across relevant levels.
Maker or taker classification concerns how a fill interacts with order-book liquidity, not simply whether you pressed Buy, Sell or Limit. One order can take existing liquidity immediately and leave another portion resting. Review each fill's role, rate and fee currency before calculating cost.