eth_estimateGas

Estimate gas needed for execution of given contract

web3.eth.estimateGas(callObject [, callback])

Parameters

1. A transaction object.

2. (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns

the used gas for the simulated call/transaction.

Example

web3.eth.estimateGas({
    from : account1,
    to : account2
}).then(console.log);
> 21000