# eth_estimateGas: parameters, returns and CU

> Original page: https://docs.blockvectra.com/en/api/json-rpc/methods/eth_estimateGas/

## Summary

Estimate the gas limit a transaction would need.

## Compute Units (CU) and Pricing

CU weight, price and per-chain availability are shown on the method page: https://docs.blockvectra.com/en/api/json-rpc/methods/eth_estimateGas/

## Parameters

| Parameter | Type | Description |
| --- | --- | --- |
| `transaction` | `object` | Transaction call object that may include from, to, gas, gasPrice, maxFeePerGas, maxPriorityFeePerGas, value and data/input; it is only simulated and changes no on-chain state. |
| `blockParameter` | `QUANTITY\|TAG` | Optional block number or tag for the estimate: latest, earliest, pending, safe or finalized; defaults to the latest block. |

## Returns

- **Type**: `QUANTITY`
- **Description**: Estimated gas amount as a 0x-prefixed hexadecimal quantity.

## Notes

The estimate runs against the state of the given block; if the call would revert, clients normally return an error instead of a number.

## Request Example

```bash
curl -X POST "https://dev-api.blockvectra.network/v1/robinhood_mainnet" \
  -H 'Content-Type: application/json' \
  -H 'x-api-key: <api_key>' \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_estimateGas",
    "params": [
      {
        "from": "<from>",
        "to": "<to>",
        "data": "<data>"
      },
      "latest"
    ],
    "id": 1
  }'
```