> ## Documentation Index
> Fetch the complete documentation index at: https://docs.chainstack.com/llms.txt
> Use this file to discover all available pages before exploring further.
## Submitting Feedback
If you encounter incorrect, outdated, or confusing documentation on this page, submit feedback:
POST https://docs.chainstack.com/feedback
```json
{
"path": "/reference/ethereum-estimategas",
"feedback": "Description of the issue"
}
```
Only submit feedback when you have something specific and actionable to report.
# eth_estimateGas | Ethereum
Ethereum API method that returns an estimate of gas units needed for a given transaction.
It provides an estimate of the maximum amount of gas units required to complete the transaction based on the network's current state and the transaction's parameters. A client or wallet can use this estimate to determine the appropriate amount of gas to include in a transaction to ensure that the network processes it.
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## Parameters
* `object` — the transaction call object, same as in `eth_call`; the `from` field is optional, and the `nonce` field is omitted:
* `from` — (optional) the string of the address used to send the transaction.
* `to` — the string of the address to which the transaction is directed, a wallet, or a smart contract.
* `gas` — (optional) the maximum amount of gas that can be used by the transaction.
* `gasprice` — (optional) the amount of gas price the sender is willing to pay for each gas unit in [Wei](https://ethereum.org/en/developers/docs/intro-to-ether/#denominations).
* `value` — (optional) the value sent with this transaction, encoded as hexadecimal.
* `data` — (optional) additional data to be sent with the call, usually used to invoke functions from smart contracts as a string of the hash of the method signature and encoded parameters; see the [Ethereum Contract ABI](https://solidity.readthedocs.io/en/latest/abi-spec.html).
* `quantity or tag` — the integer of a block encoded as hexadecimal or the string with:
* `latest` — the most recent block in the blockchain and the current state of the blockchain at the most recent block. A chain reorganization is to be expected.
* `safe` — the block that received justification from the beacon chain. Although this block could be involved in a chain reorganization, it would necessitate either a coordinated attack by the majority of validators or an instance of severe propagation latency.
* `finalized` — the block accepted as canonical by more than 2/3 of the validators. A chain reorganization is extremely unlikely, and it would require at least 1/3 of the staked ETH to be burned.
* `earliest` — the earliest available or genesis block
* `pending` — the pending state and transactions block. The current state of transactions that have been broadcast to the network but have not yet been included in a block.
See the [default block parameter](https://eth.wiki/json-rpc/API#the-default-block-parameter) and [How The Merge Impacts Ethereum’s Application Layer](https://blog.ethereum.org/2021/11/29/how-the-merge-impacts-app-layer).
## Response
* `quantity` — the estimated amount of gas units needed, represented as a hexadecimal string.
## `eth_estimateGas` code examples
Learn more about the `ChainstackProvider` in `ethers.js`: [ethers ChainstackProvider Documentation](/reference/ethersjs-chainstackprovider).
```javascript ethers.js theme={"system"}
const ethers = require("ethers");
// Create a ChainstackProvider instance for Ethereum mainnet
const chainstack = new ethers.ChainstackProvider("mainnet");
const estimateGas = async () => {
// The transaction to estimate is a simple transfer in this example.
const transactionObj = {
from: "0xCb6Ed7E78d27FDff28127F9CbD61d861F09a2324",
to: "0xbe0eb53f46cd790cd13851d5eff43d12404d33e8",
};
const gasUnits = await chainstack.estimateGas(transactionObj);
console.log(`Estimated gas units required: ${gasUnits}`);
};
estimateGas();
```
```javascript web3.js theme={"system"}
const { Web3 } = require("web3");
const NODE_URL = "CHAINSTACK_NODE_URL";
const web3 = new Web3(NODE_URL);
async function estimateGas() {
// The transaction to estimate is a simple transfer in this example.
const transactionObj = {
from: "0xCb6Ed7E78d27FDff28127F9CbD61d861F09a2324",
to: "0xbe0eb53f46cd790cd13851d5eff43d12404d33e8",
}
const gasUnits = await web3.eth.estimateGas(transactionObj);
console.log(`Estimated gas units required: ${gasUnits}`);
}
estimateGas()
```
```python web3.py theme={"system"}
from web3 import Web3
node_url = "CHAINSTACK_NODE_URL"
web3 = Web3(Web3.HTTPProvider(node_url))
print(web3.eth.estimate_gas({"from":"0xCb6Ed7E78d27FDff28127F9CbD61d861F09a2324","to":"0xbe0eb53f46cd790cd13851d5eff43d12404d33e8"}, "latest" ))
```
## Use case
A practical use case for `eth_estimateGas` is to calculate the gas cost required for a transaction that transfers a value from one Ethereum address (`fromAddress`) to another (`toAddress`). The gas cost is an important factor in transactions, as it determines the amount of fees that need to be paid by the sender to the network for processing the transaction.
```javascript index.js theme={"system"}
const { Web3 } = require("web3");
const NODE_URL = "CHAINSTACK_NODE_URL";
const web3 = new Web3(NODE_URL);
async function estimateGasCost(from, to, value) {
try {
const gasEstimate = await web3.eth.estimateGas({ from: from, to: to, value: value });
return gasEstimate
} catch (error) {
console.error(`Error estimating gas cost: ${error}`);
}
}
async function main() {
const fromAddress = '0xae2Fc483527B8EF99EB5D9B44875F005ba1FaE13';
const toAddress = '0x81ab6Fd4A68d0aDDFAD65F9F97Bc1427dCd40C8E';
const value = web3.utils.toWei("25", "ether" )
const estimatedGas= await estimateGasCost(fromAddress, toAddress, value)
if (estimatedGas) {
console.log(`Estimated gas cost: ${estimatedGas}`);
}
}
main()
```
The `estimateGasCost` function wraps the call to `eth.estimateGas` in a `try-catch` block so that any errors that occur during the estimation process can be handled gracefully. If an error occurs, the error message is logged to the console. If the estimate is successful, the estimated gas cost is returned.
The main function is the entry point of the code. It sets the `fromAddress`, `toAddress`, and value for the transaction, and then calls the `estimateGasCost` function to get the estimated gas cost. The estimated gas cost is logged to the console if the estimate is successful, but it is available to be used for further processing in the `estimatedGas` constant.
## OpenAPI
````yaml /openapi/ethereum_node_api/gas_data/eth_estimateGas.json POST /0a9d79d93fb2f4a4b1e04695da2b77a7
openapi: 3.0.0
info:
title: Chainstack Node API
version: 1.0.0
description: This is an API for interacting with a Chainstack node.
servers:
- url: https://nd-422-757-666.p2pify.com
security: []
paths:
/0a9d79d93fb2f4a4b1e04695da2b77a7:
post:
tags:
- upload
summary: eth_estimateGas
operationId: estimateGas
requestBody:
required: true
content:
application/json:
schema:
type: object
properties:
id:
type: integer
default: 1
jsonrpc:
type: string
default: '2.0'
method:
type: string
default: eth_estimateGas
params:
type: array
items:
type: object
properties:
from:
type: string
format: byte
to:
type: string
format: byte
default:
- from: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045'
to: '0xbe0eb53f46cd790cd13851d5eff43d12404d33e8'
- latest
responses:
'200':
description: The estimated gas amount
content:
application/json:
schema:
type: object
properties:
jsonrpc:
type: string
id:
type: integer
result:
type: string
format: byte
````