> ## Documentation Index
> Fetch the complete documentation index at: https://align.tolbel.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Estimate Gas

> Calculate the gas cost for a transaction before sending

## Method Signature

```typescript theme={null}
align.blockchain.transactions.estimateGas(
  from: string,
  to: string,
  amount: string,
  network: Network,
  data?: string
): Promise<GasEstimate>
```

## Parameters

<ParamField body="from" type="string" required>
  Sender wallet address
</ParamField>

<ParamField body="to" type="string" required>
  Recipient address
</ParamField>

<ParamField body="amount" type="string" required>
  Amount in native token (e.g., `"0.1"`)
</ParamField>

<ParamField body="network" type="string" required>
  Network: `ethereum`, `polygon`, `base`, `arbitrum`
</ParamField>

<ParamField body="data" type="string">
  Optional encoded contract call data (for contract interactions)
</ParamField>

## Returns

<ResponseField name="gasLimit" type="string">
  Estimated gas units required
</ResponseField>

<ResponseField name="gasPrice" type="string">
  Current gas price in wei
</ResponseField>

<ResponseField name="maxFeePerGas" type="string">
  EIP-1559 max fee per gas
</ResponseField>

<ResponseField name="maxPriorityFeePerGas" type="string">
  EIP-1559 priority fee
</ResponseField>

<ResponseField name="estimatedCost" type="string">
  Total estimated cost in native token
</ResponseField>

## Examples

<Tabs>
  <Tab title="TypeScript">
    ```typescript theme={null}
    import Align from "@tolbel/align";

    const align = new Align({
      apiKey: process.env.ALIGN_API_KEY!,
      environment: "sandbox",
    });

    const estimate = await align.blockchain.transactions.estimateGas(
      "0xSenderAddress...",
      "0xRecipientAddress...",
      "0.1",
      "polygon"
    );

    console.log(`Gas Limit: ${estimate.gasLimit}`);
    console.log(`Estimated Cost: ${estimate.estimatedCost} POL`);
    ```
  </Tab>

  <Tab title="JavaScript">
    ```javascript theme={null}
    const estimate = await align.blockchain.transactions.estimateGas(
      from,
      to,
      "0.1",
      "polygon"
    );
    console.log("Cost:", estimate.estimatedCost, "POL");
    ```
  </Tab>
</Tabs>

### Show Fee to User Before Send

```typescript theme={null}
const estimate = await align.blockchain.transactions.estimateGas(
  wallet.address,
  recipient,
  sendAmount,
  "polygon"
);

// Display to user
console.log(`
  Transaction Summary:
  - Sending: ${sendAmount} POL
  - Network Fee: ${estimate.estimatedCost} POL
  - Total: ${parseFloat(sendAmount) + parseFloat(estimate.estimatedCost)} POL
`);

// Check if user has enough
const balance = await align.blockchain.wallets.getBalance(
  wallet.address,
  "polygon"
);
const totalNeeded = parseFloat(sendAmount) + parseFloat(estimate.estimatedCost);

if (parseFloat(balance) < totalNeeded) {
  throw new Error(`Insufficient balance. Need ${totalNeeded}, have ${balance}`);
}
```

<Tip>
  Gas estimates include a buffer for safety. Unused gas is returned to the
  sender.
</Tip>

## Related Methods

<CardGroup cols={2}>
  <Card title="Send Native Token" icon="paper-plane" href="/docs/api/blockchain/wallets/send-native-token">
    Send transaction
  </Card>

  <Card title="Get Status" icon="clock" href="/docs/api/blockchain/transactions/get-status">
    Check transaction status
  </Card>
</CardGroup>