eth_estimateGas

The eth_estimateGas method generates and returns an estimate of how much gas is necessary to allow the transaction to complete. This method simulates the transaction execution and calculates the gas needed, which is crucial for wallet applications to show users the transaction cost before they confirm.

The estimate includes a small buffer to account for state changes between estimation and actual execution. Developers use this to provide accurate gas estimates to users, prevent out-of-gas errors, and optimize gas usage. The method executes the transaction simulation at the specified block state and returns the amount of gas consumed. Note that the actual gas used may differ slightly if blockchain state changes between estimation and execution, so it's common to add a small buffer (e.g., 10-20%) when setting the gas limit.

Parameters

parameter	type	description
transaction	object (required)	Transaction object containing the details of the call to estimate
blockParameter	string (optional)	Block number in hex format (e.g., '0x10d4f') or one of the string tags: 'latest', 'earliest', or 'pending'. Defaults to 'latest' if omitted

Transaction Object Properties:

property	type	description
from	string (optional)	The address the transaction is sent from (20-byte hex string)
to	string (optional)	The address the transaction is directed to (20-byte hex string). Null for contract creation
gas	string (optional)	Maximum gas provided for the transaction (hex). If omitted, the node uses a maximum value
gasPrice	string (optional)	Gas price for legacy transactions (hex)
maxFeePerGas	string (optional)	Maximum fee per gas for EIP-1559 transactions (hex)
maxPriorityFeePerGas	string (optional)	Maximum priority fee per gas for EIP-1559 transactions (hex)
value	string (optional)	Value sent with the transaction in wei (hex)
data	string (optional)	Compiled contract code or encoded function call data (hex)

Return Object

field	type	description
result	string	The estimated gas amount required for the transaction encoded as a hexadecimal string. This represents the number of gas units the transaction would consume if executed. To calculate the total cost in FLR, multiply this value by the gas price (result * gasPrice = total cost in wei).

Request Example

Request

Response Example

Response