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

# Gas 估算

> 使用 Simulation API 的 estimate_gas 估算 gas，或在发送前通过 tenderly_estimateGas RPC 方法获取 100% 精确的 gas 限额。

Simulation API 允许您模拟交易并获取成功执行该交易所需的预计 gas 用量。

在请求中设置 `estimate_gas: true` 即可获取 gas 估算。

<Note>
  注意：您可以使用 [**`tenderly_estimateGas`**](/node-rpc/rpc-reference?network=ethereum-mainnet\&method=tenderly_estimateGas) 和 [**`tenderly_estimateGasBundle`**](/node-rpc/rpc-reference?network=ethereum-mainnet\&method=tenderly_estimateGasBundle) RPC 方法获取 100% 精确的 gas 估算。
</Note>

**示例**

请务必将访问密钥安全地存储在 `.env` 文件中。

```ts title="example.ts" showLineNumbers theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}

dotenv.config();

const { TENDERLY_ACCOUNT_SLUG, TENDERLY_PROJECT_SLUG, TENDERLY_ACCESS_KEY } = process.env;

const simulateTransaction = async () => {
  const { data } = await axios.post(
    `https://api.tenderly.co/api/v1/account/${TENDERLY_ACCOUNT_SLUG}/project/${TENDERLY_PROJECT_SLUG}/simulate`,
    {
      // Simulation Configuration
      save: true,
      save_if_fails: false,
      estimate_gas: true,
      simulation_type: 'quick',
      network_id: '1',
      // Standard EVM Transaction object (sample values)
      from: '0xdc6bdc37b2714ee601734cf55a05625c9e512461',
      to: '0x6b175474e89094c44da98b954eedeac495271d0f',
      input: '0x095ea7b3000000000000000000000000f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1000000000000000000000000000000000000000000000000000000000000012b',
      gas: 8000000,
      gas_price: 0,
      value: 0,
    },
    {
      headers: {
        'X-Access-Key': TENDERLY_ACCESS_KEY as string,
      },
    },
  );

  console.log({ data });
};

simulateTransaction();
```

此操作会计算交易所需的最大 gas 用量。模拟成功后，请检查 `transaction` 结构中的 `gas_used` 字段。

**结果**

```json title="example.json" showLineNumbers theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
"transaction": {
    ...
    "gas": 8000000,
    "gas_price": 0,
    "gas_fee_cap": 0,
    "gas_tip_cap": 0,
    "cumulative_gas_used": 0,
    "gas_used": 51534, // Gas estimates
    "effective_gas_price": 0,
    ...
 }
```