eth_estimateGas

eth_estimateGas simulates a transaction against current Base state and returns the amount of gas it would need to execute on-chain, without actually submitting it. Base is Coinbase's OP Stack rollup where ETH pays for gas, so the figure you get back is the L2 execution gas you must cover when the transaction lands. Send the request to https://base.therpc.io/YOUR_API_KEY (chain ID 8453) and the node runs the call, adds a small safety buffer, and hands back a hex gas estimate you can plug into the transaction's gas limit.

Use cases

• Calculate the gas limit to set on a Base transaction before signing it, so it neither runs out of gas nor over-reserves.
• Estimate the deployment cost of a new contract on Base by omitting to and passing the deploy bytecode as data.
• Check whether a transaction would succeed at all — a clean estimate means the call did not revert against current state.
• Drive live fee estimates in Base wallets and dApps, combining the gas units here with current fee data from eth_feeHistory.

Parameters

Response

Example request

1curl https://base.therpc.io/YOUR_API_KEY \
2  -X POST \
3  -H "Content-Type: application/json" \
4  -d '{
5    "jsonrpc": "2.0",
6    "method": "eth_estimateGas",
7    "params": [
8        {
9          "to": "0x0000000000000000000000000000000000000000",
10          "data": "0x"
11        },
12        "latest"
13      ],
14    "id": 1
15  }'

Try it live in the Base playground.

Errors & troubleshooting

Common pitfalls

• The estimate is not a hard guarantee — set the actual gas limit slightly above it (around ×1.2) so an edge case doesn't trigger an out-of-gas failure on Base.
• If the simulated transaction reverts, you get a JSON-RPC error (code 3 or -32000) instead of a gas figure, so handle that path explicitly.
• Gas usage can shift between estimation and execution if contract state changes in between; on Base's ~2s blocks the window is small but real for hot contracts like Aerodrome pools.

Supported networks

• Mainnet — Chain ID: 8453
• Sepolia — Chain ID: 84532

See also

• eth_call
• eth_sendRawTransaction
• eth_gasPrice
• eth_feeHistory

1curl https://base.therpc.io/YOUR_API_KEY \
2  -X POST \
3  -H 'Content-Type: application/json' \
4  -d '{"jsonrpc":"2.0","id":1,"method":"eth_estimateGas","params":[{"to":"0x0000000000000000000000000000000000000000","data":"0x"},"",null]}'