eth_estimateGas

Generates and returns an estimate of how much gas is necessary to allow the transaction to complete. The transaction will not be added to the blockchain.

When to Use This Method

eth_estimateGas is crucial for:

Transaction Preparation - Calculate gas limits before sending
Cost Estimation - Preview transaction fees for users
Gas Optimization - Find optimal gas usage for complex operations
Error Prevention - Detect failures before broadcasting

Parameters

Transaction Object
- from - (optional) Address sending the transaction
- to - Address of receiver or contract
- gas - (optional) Gas limit for estimation
- gasPrice - (optional) Gas price in wei
- value - (optional) Value to send in wei
- data - (optional) Hash of method signature and encoded parameters
Block Parameter - QUANTITY|TAG (optional)
- "latest" - Most recent block (default)
- "pending" - Pending state
- Block number in hex

{
  "jsonrpc": "2.0",
  "method": "eth_estimateGas",
  "params": [
    {
      "from": "0xb60e8dd61c5d32be8058bb8eb970870f07233155",
      "to": "0xd46e8dd67c5d32be8058bb8eb970870f07244567",
      "value": "0x9184e72a",
      "data": "0xd46e8dd67c5d32be8058bb8eb970870f072445675058bb8eb970870f072445675"
    }
  ],
  "id": 1
}

Returns

QUANTITY - The estimated gas amount in hexadecimal.

Implementation Examples

JavaScript
Python

import { JsonRpcProvider, Contract, parseEther, parseUnits } from 'ethers';

const provider = new JsonRpcProvider('https://api-manta-pacific-mainnet.n.dwellir.com/YOUR_API_KEY');

// Gas estimation utility
class GasEstimator {
  constructor(provider) {
    this.provider = provider;
    this.cache = new Map();
  }

  async estimateETHTransfer(from, to, value) {
    try {
      const gasEstimate = await this.provider.estimateGas({
        from: from,
        to: to,
        value: parseEther(value)
      });

      // Add 10% buffer for safety
      const gasWithBuffer = gasEstimate * 110n / 100n;

      // Get current gas prices
      const feeData = await this.provider.getFeeData();
      
      // Calculate costs
      const estimatedCost = gasWithBuffer * feeData.gasPrice;
      const estimatedCostEIP1559 = gasWithBuffer * feeData.maxFeePerGas;

      return {
        gasLimit: gasWithBuffer.toString(),
        gasPrice: feeData.gasPrice.toString(),
        maxFeePerGas: feeData.maxFeePerGas.toString(),
        maxPriorityFeePerGas: feeData.maxPriorityFeePerGas.toString(),
        estimatedCostWei: estimatedCost.toString(),
        estimatedCostETH: ethers.formatEther(estimatedCost),
        estimatedCostEIP1559Wei: estimatedCostEIP1559.toString(),
        estimatedCostEIP1559ETH: ethers.formatEther(estimatedCostEIP1559)
      };
    } catch (error) {
      throw new Error(`Gas estimation failed: ${error.message}`);
    }
  }

  async estimateContractCall(contractAddress, abi, method, params, from) {
    const contract = new Contract(contractAddress, abi, this.provider);
    
    try {
      // Build transaction
      const tx = await contract[method].populateTransaction(...params);
      tx.from = from;

      // Estimate gas
      const gasEstimate = await this.provider.estimateGas(tx);
      const l2Cost = gasWithBuffer * feeData.maxFeePerGas;
      const totalCost = l2Cost;

      return {
        gasLimit: gasWithBuffer.toString(),
        l2GasEstimate: gasEstimate.toString(),        maxFeePerGas: feeData.maxFeePerGas.toString(),
        l2CostWei: l2Cost.toString(),
        l2CostETH: ethers.formatEther(l2Cost),
        totalCostWei: totalCost.toString(),
        totalCostETH: ethers.formatEther(totalCost),
        method: method,
        contract: contractAddress
      };
    } catch (error) {
      // Parse revert reason if available
      if (error.data) {
        const reason = this.parseRevertReason(error.data);
        throw new Error(`Estimation failed: ${reason}`);
      }
      throw error;
    }
  }  parseRevertReason(data) {
    if (typeof data === 'string' && data.startsWith('0x08c379a0')) {
      // Standard revert string
      const reason = ethers.AbiCoder.defaultAbiCoder().decode(
        ['string'],
        '0x' + data.slice(10)
      )[0];
      return reason;
    }
    return 'Unknown error';
  }

  async batchEstimate(transactions) {
    const estimates = [];
    
    for (const tx of transactions) {
      try {
        const gasEstimate = await this.provider.estimateGas(tx);
        const feeData = await this.provider.getFeeData();
        
        estimates.push({
          transaction: tx,
          gasLimit: gasEstimate.toString(),
          estimatedCost: (gasEstimate * feeData.maxFeePerGas).toString(),
          success: true
        });
      } catch (error) {
        estimates.push({
          transaction: tx,
          error: error.message,
          success: false
        });
      }
    }
    
    return estimates;
  }

  async compareGasStrategies(transaction) {
    const gasEstimate = await this.provider.estimateGas(transaction);
    const feeData = await this.provider.getFeeData();
    const block = await this.provider.getBlock('latest');
    
    // Different gas strategies
    const strategies = {
      conservative: {
        gasLimit: gasEstimate * 150n / 100n, // 50% buffer
        maxFeePerGas: feeData.maxFeePerGas * 120n / 100n,
        maxPriorityFeePerGas: feeData.maxPriorityFeePerGas * 120n / 100n
      },
      standard: {
        gasLimit: gasEstimate * 110n / 100n, // 10% buffer
        maxFeePerGas: feeData.maxFeePerGas,
        maxPriorityFeePerGas: feeData.maxPriorityFeePerGas
      },
      aggressive: {
        gasLimit: gasEstimate * 105n / 100n, // 5% buffer
        maxFeePerGas: block.baseFeePerGas * 2n + feeData.maxPriorityFeePerGas / 2n,
        maxPriorityFeePerGas: feeData.maxPriorityFeePerGas / 2n
      }
    };
    
    const results = {};
    for (const [name, strategy] of Object.entries(strategies)) {
      const maxCost = strategy.gasLimit * strategy.maxFeePerGas;
      const likelyCost = strategy.gasLimit * 
        (block.baseFeePerGas + strategy.maxPriorityFeePerGas);
      
      results[name] = {
        ...strategy,
        maxCostWei: maxCost.toString(),
        maxCostETH: ethers.formatEther(maxCost),
        likelyCostWei: likelyCost.toString(),
        likelyCostETH: ethers.formatEther(likelyCost)
      };
    }
    
    return results;
  }
}

// Usage example
const estimator = new GasEstimator(provider);

// Estimate simple transfer
const transferEstimate = await estimator.estimateETHTransfer(
  '0xYourAddress',
  '0xRecipientAddress',
  '0.1'
);
console.log('Transfer cost:', transferEstimate.estimatedCostETH, 'ETH');

// Estimate contract interaction
const contractEstimate = await estimator.estimateContractCall(
  '0xContractAddress',
  ['function transfer(address to, uint256 amount)'],
  'transfer',
  ['0xRecipient', parseUnits('100', 18)],
  '0xYourAddress'
);
console.log('Contract call cost:', contractEstimate.totalCostETH, 'ETH');

from web3 import Web3
from eth_utils import to_wei, from_wei
import json
from typing import Dict, Any, List, Optional

w3 = Web3(Web3.HTTPProvider('https://api-manta-pacific-mainnet.n.dwellir.com/YOUR_API_KEY'))

class GasCalculator:
    """Calculate and optimize gas for Manta Pacific L2 transactions"""
    
    def __init__(self, w3_instance):
        self.w3 = w3_instance
    
    def estimate_transfer(
        self, 
        from_address: str, 
        to_address: str, 
        value_eth: float
    ) -> Dict[str, Any]:
        """Estimate gas for ETH transfer"""
        
        try:
            # Build transaction
            transaction = {
                'from': from_address,
                'to': to_address,
                'value': to_wei(value_eth, 'ether')
            }
            
            # Estimate gas
            gas_estimate = self.w3.eth.estimate_gas(transaction)
            
            # Add buffer
            gas_limit = int(gas_estimate * 1.1)  # 10% buffer
            
            # Get current gas prices
            gas_price = self.w3.eth.gas_price
            base_fee = self.w3.eth.get_block('latest')['baseFeePerGas']
            max_priority_fee = self.w3.eth.max_priority_fee
            
            # Calculate costs
            estimated_cost = gas_limit * gas_price
            max_cost = gas_limit * (base_fee * 2 + max_priority_fee)
            
            return {
                'gas_estimate': gas_estimate,
                'gas_limit': gas_limit,
                'gas_price_gwei': from_wei(gas_price, 'gwei'),
                'base_fee_gwei': from_wei(base_fee, 'gwei'),
                'priority_fee_gwei': from_wei(max_priority_fee, 'gwei'),
                'estimated_cost_eth': from_wei(estimated_cost, 'ether'),
                'max_cost_eth': from_wei(max_cost, 'ether')
            }
            
        except Exception as e:
            return {'error': str(e)}
    
    def estimate_contract_call(
        self,
        from_address: str,
        to_address: str,
        data: str,
        value: int = 0
    ) -> Dict[str, Any]:
        """Estimate gas for contract interaction"""
        
        transaction = {
            'from': from_address,
            'to': to_address,
            'data': data,
            'value': value
        }
        
        try:
            # Estimate gas
            gas_estimate = self.w3.eth.estimate_gas(transaction)
            

            return {'gas_estimate': gas_estimate}
        except Exception as e:
            return {'error': str(e)}

When to Use This Method​

Parameters​

Returns​

Implementation Examples​

When to Use This Method

Parameters

Returns

Implementation Examples