eth_estimateGas

Generates and returns an estimate of how much gas is necessary to allow the transaction to complete.

Important

The transaction will not be added to the blockchain. The estimate may be significantly different from the actual gas used if the transaction modifies the state.

When to Use This Method

Use eth_estimateGas to:

Prevent Failed Transactions - Ensure sufficient gas before sending
Optimize Gas Usage - Find optimal gas limits
Cost Prediction - Calculate transaction fees in advance
Cross-Chain Planning - Estimate omnichain operation costs
Smart Contract Testing - Validate contract calls before execution

Parameters

Transaction Object (required):
- from (optional): 20 bytes - Address the transaction is sent from
- to (required): 20 bytes - Address the transaction is directed to
- gas (optional): Gas limit for estimation
- gasPrice (optional): Gas price for estimation
- value (optional): Value sent with transaction
- data (optional): Method signature and encoded parameters
Block Parameter (optional):
- latest - Latest block (default)
- pending - Pending state
- Block number as hexadecimal

{
  "jsonrpc": "2.0",
  "method": "eth_estimateGas",
  "params": [
    {
      "from": "0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb8",
      "to": "0xd46e8dd67c5d32be8058bb8eb970870f07244567",
      "value": "0xde0b6b3a7640000",
      "data": "0xa9059cbb000000000000000000000000..."
    },
    "latest"
  ],
  "id": 1
}

Returns

QUANTITY - The estimated gas amount.

Type: Hexadecimal string
Unit: Gas units
Format: 0x prefixed

Implementation Examples

cURL
JavaScript
Python

# Estimate simple transfer
curl -X POST https://api-xdc-mainnet.n.dwellir.com/YOUR_API_KEY \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_estimateGas",
    "params": [
      {
        "from": "0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb8",
        "to": "0xd46e8dd67c5d32be8058bb8eb970870f07244567",
        "value": "0xde0b6b3a7640000"
      },
      "latest"
    ],
    "id": 1
  }'

# Estimate contract interaction
curl -X POST https://api-xdc-mainnet.n.dwellir.com/YOUR_API_KEY \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_estimateGas",
    "params": [
      {
        "from": "0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb8",
        "to": "0x5F0b1a82749cb4E2278EC87F8BF6B618dC71a8bf",
        "data": "0xa9059cbb000000000000000000000000d46e8dd67c5d32be8058bb8eb970870f072445670000000000000000000000000000000000000000000000000de0b6b3a7640000"
      },
      "latest"
    ],
    "id": 1
  }'

// Using fetch
const estimateGas = async (transaction) => {
  const response = await fetch('https://api-xdc-mainnet.n.dwellir.com/YOUR_API_KEY', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({
      jsonrpc: '2.0',
      method: 'eth_estimateGas',
      params: [transaction, 'latest'],
      id: 1,
    }),
  });
  
  const data = await response.json();
  return BigInt(data.result);
};

// Using ethers.js
import { ethers } from 'ethers';

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

// Estimate simple transfer
const estimateTransfer = await provider.estimateGas({
  from: '0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb8',
  to: '0xd46e8dd67c5d32be8058bb8eb970870f07244567',
  value: ethers.parseEther('1.0')
});
console.log('Transfer gas estimate:', estimateTransfer.toString());

// Estimate contract call
const tokenContract = new ethers.Contract(tokenAddress, tokenABI, provider);
const estimateTokenTransfer = await tokenContract.transfer.estimateGas(
  '0xd46e8dd67c5d32be8058bb8eb970870f07244567',
  ethers.parseEther('100')
);
console.log('Token transfer estimate:', estimateTokenTransfer.toString());

// Estimate cross-chain operation
const omnichainContract = new ethers.Contract(omnichainAddress, omnichainABI, provider);
const estimateCrossChain = await omnichainContract.sendCrossChain.estimateGas(
  56, // BSC chain ID
  '0xrecipient',
  ethers.parseEther('10'),
  { value: ethers.parseEther('0.01') } // Protocol fee
);
console.log('Cross-chain estimate:', estimateCrossChain.toString());

// Using web3.js
import Web3 from 'web3';

const web3 = new Web3('https://api-xdc-mainnet.n.dwellir.com/YOUR_API_KEY');

const gasEstimate = await web3.eth.estimateGas({
  from: '0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb8',
  to: '0xd46e8dd67c5d32be8058bb8eb970870f07244567',
  value: web3.utils.toWei('1', 'ether')
});
console.log('Estimated gas:', gasEstimate);

import requests
import json
from web3 import Web3

# Using requests
url = 'https://api-xdc-mainnet.n.dwellir.com/YOUR_API_KEY'

def estimate_gas(transaction):
    payload = {
        'jsonrpc': '2.0',
        'method': 'eth_estimateGas',
        'params': [transaction, 'latest'],
        'id': 1
    }
    
    response = requests.post(url, json=payload)
    result = response.json()
    return int(result['result'], 16)

# Simple transfer
tx = {
    'from': '0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb8',
    'to': '0xd46e8dd67c5d32be8058bb8eb970870f07244567',
    'value': '0xde0b6b3a7640000'  # 1 ZETA
}

gas_needed = estimate_gas(tx)
print(f'Gas estimate: {gas_needed}')

# Using web3.py
w3 = Web3(Web3.HTTPProvider('https://api-xdc-mainnet.n.dwellir.com/YOUR_API_KEY'))

# Estimate simple transfer
gas_estimate = w3.eth.estimate_gas({
    'from': '0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb8',
    'to': '0xd46e8dd67c5d32be8058bb8eb970870f07244567',
    'value': w3.to_wei(1, 'ether')
})
print(f'Transfer gas estimate: {gas_estimate}')

# Estimate contract interaction
contract = w3.eth.contract(address=token_address, abi=token_abi)
gas_estimate = contract.functions.transfer(
    '0xd46e8dd67c5d32be8058bb8eb970870f07244567',
    w3.to_wei(100, 'ether')
).estimate_gas({'from': '0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb8'})
print(f'Token transfer estimate: {gas_estimate}')

Example Response

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x5208"
}

Decoding: 0x5208 = 21,000 gas units (standard transfer)

Omnichain Gas Estimation

xdc requires special gas considerations for cross-chain operations:

Cross-Chain Gas Calculator

class CrossChainGasEstimator {
  constructor(provider) {
    this.provider = provider;
    this.connectorAddress = '0x239e96c8f17C85c30100AC26F635Ea15f23E9c67';
  }
  
  async estimateCrossChainOperation(params) {
    const {
      sourceChain,
      destChain,
      operation,
      data,
      value
    } = params;
    
    // Estimate xdc gas
    const zetaGas = await this.estimatexdcGas(operation, data);
    
    // Estimate destination chain gas
    const destGas = await this.estimateDestinationGas(destChain, operation);
    
    // Calculate protocol fees
    const protocolFee = await this.getProtocolFee(sourceChain, destChain);
    
    return {
      xdcGas: zetaGas,
      destinationGas: destGas,
      protocolFee: protocolFee,
      totalGas: zetaGas + destGas,
      estimatedCost: await this.calculateCost(zetaGas + destGas, protocolFee)
    };
  }
  
  async estimatexdcGas(operation, data) {
    const tx = {
      to: this.connectorAddress,
      data: this.encodeOperation(operation, data)
    };
    
    return await this.provider.estimateGas(tx);
  }
  
  async estimateDestinationGas(chainId, operation) {
    // Chain-specific gas requirements
    const gasRequirements = {
      1: 150000,    // Ethereum
      56: 100000,   // BSC
      137: 80000,   // Polygon
      43114: 120000 // Avalanche
    };
    
    return BigInt(gasRequirements[chainId] || 100000);
  }
}

Common Use Cases

1. Safe Transaction Sender

class SafeTransactionSender {
  constructor(signer) {
    this.signer = signer;
    this.bufferPercentage = 20; // 20% buffer
  }
  
  async sendTransaction(transaction) {
    try {
      // Estimate gas
      const estimatedGas = await this.signer.estimateGas(transaction);
      
      // Add buffer for safety
      const gasLimit = estimatedGas * BigInt(100 + this.bufferPercentage) / 100n;
      
      // Get current gas price
      const gasPrice = await this.signer.provider.getGasPrice();
      
      // Calculate total cost
      const totalCost = gasLimit * gasPrice;
      const balance = await this.signer.provider.getBalance(transaction.from || await this.signer.getAddress());
      
      // Check sufficient balance
      if (balance < totalCost + (transaction.value || 0n)) {
        throw new Error(`Insufficient balance. Need ${ethers.formatEther(totalCost)} ZETA for gas`);
      }
      
      // Send transaction with safe gas limit
      const tx = await this.signer.sendTransaction({
        ...transaction,
        gasLimit
      });
      
      console.log('Transaction sent:', tx.hash);
      console.log('Gas limit used:', gasLimit.toString());
      
      return tx;
    } catch (error) {
      console.error('Transaction failed:', error);
      throw error;
    }
  }
}

2. Batch Transaction Estimator

async function estimateBatchTransactions(transactions) {
  const estimates = [];
  const errors = [];
  
  // Parallel estimation for efficiency
  const promises = transactions.map(async (tx, index) => {
    try {
      const gasEstimate = await provider.estimateGas(tx);
      return { index, success: true, gas: gasEstimate };
    } catch (error) {
      return { index, success: false, error: error.message };
    }
  });
  
  const results = await Promise.all(promises);
  
  let totalGas = 0n;
  for (const result of results) {
    if (result.success) {
      estimates.push({
        transaction: transactions[result.index],
        gasEstimate: result.gas,
        status: 'success'
      });
      totalGas += result.gas;
    } else {
      errors.push({
        transaction: transactions[result.index],
        error: result.error,
        status: 'failed'
      });
    }
  }
  
  const gasPrice = await provider.getGasPrice();
  const totalCost = totalGas * gasPrice;
  
  return {
    successful: estimates,
    failed: errors,
    summary: {
      totalTransactions: transactions.length,
      successfulEstimates: estimates.length,
      failedEstimates: errors.length,
      totalGasNeeded: totalGas.toString(),
      estimatedCost: ethers.formatEther(totalCost) + ' ZETA'
    }
  };
}

3. Smart Contract Deployment Estimator

async function estimateContractDeployment(bytecode, constructorArgs = []) {
  const signer = await provider.getSigner();
  const address = await signer.getAddress();
  
  // Encode constructor arguments
  const deployData = bytecode + ethers.AbiCoder.defaultAbiCoder()
    .encode(constructorTypes, constructorArgs)
    .slice(2);
  
  try {
    const gasEstimate = await provider.estimateGas({
      from: address,
      data: deployData
    });
    
    const gasPrice = await provider.getGasPrice();
    const deploymentCost = gasEstimate * gasPrice;
    
    return {
      gasEstimate: gasEstimate.toString(),
      gasPrice: ethers.formatUnits(gasPrice, 'gwei') + ' Gwei',
      estimatedCost: ethers.formatEther(deploymentCost) + ' ZETA',
      bytecodeSize: bytecode.length / 2 + ' bytes',
      recommendation: gasEstimate > 5000000n 
        ? 'Consider optimizing contract size' 
        : 'Gas usage is reasonable'
    };
  } catch (error) {
    throw new Error(`Deployment estimation failed: ${error.message}`);
  }
}

4. Dynamic Gas Limit Adjuster

class DynamicGasLimitAdjuster {
  constructor(provider) {
    this.provider = provider;
    this.history = [];
    this.maxHistory = 50;
  }
  
  async getOptimalGasLimit(transaction, urgency = 'normal') {
    // Get base estimate
    const baseEstimate = await this.provider.estimateGas(transaction);
    
    // Store in history
    this.history.push({
      estimate: baseEstimate,
      timestamp: Date.now(),
      type: this.getTransactionType(transaction)
    });
    
    if (this.history.length > this.maxHistory) {
      this.history.shift();
    }
    
    // Calculate accuracy from history
    const accuracy = this.calculateHistoricalAccuracy();
    
    // Adjust based on urgency and accuracy
    const adjustments = {
      low: 1.05,      // 5% buffer
      normal: 1.15,   // 15% buffer
      high: 1.25,     // 25% buffer
      urgent: 1.35    // 35% buffer
    };
    
    const adjustment = adjustments[urgency] || 1.15;
    const finalAdjustment = accuracy < 0.9 ? adjustment * 1.1 : adjustment;
    
    const optimalGasLimit = baseEstimate * BigInt(Math.floor(finalAdjustment * 100)) / 100n;
    
    return {
      baseEstimate: baseEstimate.toString(),
      optimalGasLimit: optimalGasLimit.toString(),
      buffer: `${Math.round((finalAdjustment - 1) * 100)}%`,
      confidence: accuracy,
      urgency
    };
  }
  
  calculateHistoricalAccuracy() {
    // Simplified accuracy calculation
    if (this.history.length < 10) return 0.8;
    return 0.95;
  }
  
  getTransactionType(tx) {
    if (!tx.to) return 'deployment';
    if (tx.data && tx.data !== '0x') return 'contract_call';
    return 'transfer';
  }
}

5. Fee Market Analyzer

async function analyzeFeeMarket() {
  const blockNumber = await provider.getBlockNumber();
  const block = await provider.getBlock(blockNumber);
  
  // Sample transactions for gas estimation
  const sampleTxs = [
    { to: '0x...', value: ethers.parseEther('1') }, // Simple transfer
    { to: tokenAddress, data: '0xa9059cbb...' },    // Token transfer
    { to: dexAddress, data: '0x38ed1739...' }       // DEX swap
  ];
  
  const estimates = [];
  for (const tx of sampleTxs) {
    try {
      const gas = await provider.estimateGas(tx);
      estimates.push(gas);
    } catch (error) {
      estimates.push(null);
    }
  }
  
  const gasPrice = await provider.getGasPrice();
  
  return {
    blockNumber,
    baseFeePerGas: block.baseFeePerGas ? ethers.formatUnits(block.baseFeePerGas, 'gwei') : 'N/A',
    currentGasPrice: ethers.formatUnits(gasPrice, 'gwei'),
    estimations: {
      simpleTransfer: estimates[0]?.toString() || 'Failed',
      tokenTransfer: estimates[1]?.toString() || 'Failed',
      dexSwap: estimates[2]?.toString() || 'Failed'
    },
    recommendations: {
      simpleTransfer: estimates[0] ? (estimates[0] * gasPrice * 110n / 100n) : null,
      tokenTransfer: estimates[1] ? (estimates[1] * gasPrice * 115n / 100n) : null,
      dexSwap: estimates[2] ? (estimates[2] * gasPrice * 120n / 100n) : null
    }
  };
}

Gas Limits Guide

Common Operations

Operation	Typical Gas	Recommended Limit
ZETA Transfer	21,000	25,000
Token Transfer	50,000-65,000	75,000
DEX Swap	150,000-250,000	300,000
NFT Mint	100,000-200,000	250,000
Cross-Chain Call	200,000-500,000	600,000
Contract Deploy	500,000-5,000,000	+20% buffer

Best Practices

Always add a buffer (10-20%) to gas estimates
Re-estimate if state changes between estimate and execution
Handle estimation failures gracefully
Consider network congestion when setting limits
Cache estimates for similar transactions

Error Handling

Common Errors

async function handleGasEstimationError(error) {
  if (error.code === 'UNPREDICTABLE_GAS_LIMIT') {
    return 'Transaction will likely fail';
  }
  if (error.code === -32000) {
    return 'Execution reverted';
  }
  if (error.code === -32602) {
    return 'Invalid transaction parameters';
  }
  return 'Unknown error';
}

Error Codes

Code	Message	Description
-32600	Invalid Request	Invalid JSON
-32602	Invalid params	Invalid method parameters
-32603	Internal error	Internal JSON-RPC error
-32000	Execution reverted	Transaction would revert
3	Execution reverted	EVM revert with reason

eth_gasPrice - Get current gas price
eth_sendRawTransaction - Send transaction
eth_call - Simulate without gas
eth_getTransactionReceipt - Check actual gas used

When to Use This Method​

Parameters​

Returns​

Implementation Examples​

Example Response​

Omnichain Gas Estimation​

Cross-Chain Gas Calculator​

Common Use Cases​

1. Safe Transaction Sender​

2. Batch Transaction Estimator​

3. Smart Contract Deployment Estimator​

4. Dynamic Gas Limit Adjuster​

5. Fee Market Analyzer​

Gas Limits Guide​

Common Operations​

Best Practices​

Error Handling​

Common Errors​

Error Codes​

Related Methods​