# 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

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

### Example

```typescript
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](https://docs.ferra.ag/integration/dlmm/typescript-sdk/swap-operations/execute-swap) - Perform the swap
* [Price Impact](https://docs.ferra.ag/integration/dlmm/typescript-sdk/swap-operations/price-impact) - Calculate market impact
* [Slippage Protection](#slippage-calculation) - Set safety limits
* [Get Pair Bins](https://docs.ferra.ag/integration/dlmm/typescript-sdk/trading-pairs/get-pair-bins) - Check liquidity