eth_estimateGas

The eth_estimateGas method generates an estimate of how much gas is necessary to allow a transaction to complete. This method simulates execution without actually writing to the blockchain, giving developers a reliable way to avoid out-of-gas errors and optimize transaction costs.

Use Cases

• Pre-calculating transaction costs for user interfaces
• Smart contract deployment cost estimation
• Transaction feasibility checking before submission
• Gas optimization analysis and cost reduction
• Preventing failed transactions due to insufficient gas
• Budget planning for batch transactions
• Determining gas limits for complex contract interactions
• Testing contract functionality without spending actual gas

Method Details

This method simulates the transaction execution and returns the estimated gas consumption, typically adding a safety buffer to the raw value.

Response Example

{
	"jsonrpc": "2.0",
	"id": 1,
	"result": "0x5208" // 21000 gas (standard ETH transfer)
}

Common Gas Estimates

Different operations require different amounts of gas:

• ETH transfer: 21,000 gas (0x5208)
• ERC20 token transfer: ~45,000-65,000 gas
• Simple smart contract call: ~30,000-100,000 gas
• Smart contract deployment: Varies widely based on contract size and complexity
• NFT minting: ~50,000-300,000 gas

For best results, always use eth_estimateGas rather than hardcoding these values, as contract updates and network conditions can change gas requirements.

Important Considerations

• The estimate includes a safety buffer and may be higher than actual usage
• The method will fail with an error if the transaction would fail on-chain
• Gas estimates may vary between different nodes and providers
• Memory-intensive operations can significantly increase gas usage
• State overrides allow for testing different scenarios without changing the blockchain

See also

• eth_call - Execute a call without creating a transaction
• eth_sendTransaction - Create and send transaction
• eth_gasPrice - Get the current gas price in wei