eth_estimateGas

Returns an estimate of how much gas a transaction would require. The reported value may exceed what the transaction actually consumes when executed.

Tip

Flashblocks: call https://mainnet-preconf.base.org with "pending" to estimate gas against the current pre-confirmed state — useful when a new transaction depends on one that has just been pre-confirmed.

Parameters

transaction (object, required)

The transaction object to estimate gas for.

Field	Type	Description
from	string	Address the transaction is sent from. Optional.
to	string	Address the transaction is sent to. Optional for contract deployments.
gas	string	Gas limit. Optional; a high default is used if omitted.
gasPrice	string	Gas price in wei for legacy transactions. Optional.
maxFeePerGas	string	EIP-1559 maximum total fee per gas. Optional.
maxPriorityFeePerGas	string	EIP-1559 maximum priority fee per gas. Optional.
value	string	Value to transfer in wei. Optional.
data	string	ABI-encoded call data. Optional.

block (string, optional)

Block to estimate against. Defaults to "latest". Pass "pending" on a Flashblocks endpoint to estimate against pre-confirmed state.

Returns

Field	Type	Description
result	string	The estimated gas amount as a hexadecimal integer.

Error codes

Code	Message	Description
-32000	execution reverted	The transaction would revert. The error data field may contain a revert reason.

Example

Request

Standard

curl https://mainnet.base.org \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_estimateGas",
    "params": [{
      "from": "0xd3CdA913deB6f4967b2Ef66ae97DE114a83bcc01",
      "to": "0x4200000000000000000000000000000000000006",
      "value": "0x2c68af0bb14000"
    }],
    "id": 1
  }'

Flashblocks (pending state)

curl https://mainnet-preconf.base.org \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_estimateGas",
    "params": [{
      "from": "0xd3CdA913deB6f4967b2Ef66ae97DE114a83bcc01",
      "to": "0x4200000000000000000000000000000000000006",
      "value": "0x2c68af0bb14000"
    }, "pending"],
    "id": 1
  }'

Response

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