eth_estimateGas

Gas on BNB Smart Chain is paid in BNB, and eth_estimateGas tells you how much a transaction will consume before you commit. The node dry-runs the call against current state on its geth-equivalent EVM, then returns the gas units the operation would burn. A BEP-20 transfer, a PancakeSwap swap, a fresh contract deployment: all of them estimate the same way. Aim it at https://bsc.therpc.io/YOUR_API_KEY (chain ID 56). The simulation never reaches a validator and changes nothing on-chain. Only the estimate comes back.

Use cases

• Derive the gas limit to stamp on a transaction before signing it with BNB.
• Estimate the up-front cost of deploying a new BEP-20 token or DeFi contract to BSC.
• Probe whether a swap or transfer would succeed, since a reverting path returns an error instead of a number.
• Power live fee figures in BSC wallets and dApp confirmation screens.

Parameters

Response

Example request

1curl https://bsc.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": "0x8894E0a0c962CB723c1976a4421c95949bE2D4E3",
10          "data": "0x"
11        },
12        "latest"
13      ],
14    "id": 1
15  }'

Try it live in the BNB Smart Chain playground.

Errors & troubleshooting

Common pitfalls

• The figure is a best-effort guess, not a ceiling. Pad it by roughly 20% so a branch that costs slightly more does not strand the transaction out of gas.
• A simulated revert yields a JSON-RPC error (often code 3), not a gas number. Branch on that case instead of parsing a missing result.
• On BSC's ~3s blocks, contract state can move between estimate and inclusion, so a Venus or PancakeSwap call may end up consuming a different amount than predicted.

Supported networks

• Mainnet — Chain ID: 56
• Testnet — Chain ID: 97

See also

• eth_call
• eth_sendRawTransaction
• eth_gasPrice
• eth_feeHistory

1curl https://bsc.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":"0x8894E0a0c962CB723c1976a4421c95949bE2D4E3","data":"0x"},"",null]}'