Calculate Swap Output

The calculateRates function is used to estimate the result of a token swap within Ferra’s Discrete Liquidity Market Maker (DLMM) system. It calculates how much output you would receive from swapping a given amount, along with estimated fees and liquidity availability.

Prerequisites

• Pair object with current state

• Input amount and direction

Basic Output Calculation

// Calculate output for a swap
const result = sdk.Swap.calculateRates(pair, {
  amount: bigint,
  swapBins: LbPairBinData[],
  xtoy: boolean,
});

Example

async function estimateSwap() {
    const pair = await sdk.Pair.getPair(pairId);
    const bins = await sdk.Pair.getPairBinsData(pairId);
    const decimals = a2b ? coinA.decimals : coinB.decimals;
    const parsedAmount = parseUnits(amount.toString(), decimals);

    const result = sdk.Swap.calculateRates(pair, {
      amount: parsedAmount,
      swapBins: bins,
      xtoy: a2b,
    });
}

Name	Type	Description
pair	DLMM.Pair	The liquidity pair object, retrieved via getPair(pairId)
amount	bigint	The amount to swap, expressed in smallest units (e.g., wei). Use parseUnits() to convert from human-readable numbers
swapBins	LbPairBinData[]	The list of liquidity bins for the pair, retrieved via getPairBinsData(pairId)
xtoy	boolean	Direction of the swap. true means swap token X to Y (A to B), false for the reverse

Property	Type	Description
amount	bigint	Input amount (as provided)
estimatedAmountIn	bigint	Estimated actual input required to complete the swap
estimatedAmountOut	bigint	Estimated amount received from the swap
estimatedFeeAmount	bigint	Estimated fee deducted during the swap
isExceed	boolean	Indicates whether the requested amount exceeds available liquidity
estimatedEndBinId	bigint	The estimated ending square root price
isMaxLoop	boolean	Indicates if the estimated amount exceeds the limit
priceImpactPct	number	The price impact percentage

Important Notes

• Output depends on current bin liquidity

• Large swaps may have significant impact

• Always include fees in calculations

Related Topics

• Execute Swap - Perform the swap

• Price Impact - Calculate market impact

• Slippage Protection - Set safety limits

• Get Pair Bins - Check liquidity