I want to use whatever ethereum is available in my account as transaction fee to send a token transaction. I know the gas I need, so in theory I thought the following formula would work:

gasPrice = balanceInWei / gas

so I tried with 0.001 ETH:

gasPrice = 1000000000000000 Wei / 130091

which results in 0.000000007686926843 ETH per gas unit

But I got

Error: Returned error: insufficient funds for gas * price + value

I am sending no value, so in theory the gas * price do match the funds.

What am I missing? Do I have to use a minimum of 1 gwei as gas?

I am using Web3js version 5.6.0. Here's the code:

function main() {
    console.log('Transferring from address 0x8..');
    web3.eth.getTransactionCount(SOURCE_WALLET_ADDRESS).then(function (nonce) {
        console.log('The nonce is ' + nonce);
        web3.eth.getBalance(SOURCE_WALLET_ADDRESS).then(function (balance) { 

            console.log('Balance ' + balance); 
            sendTransaction(nonce, balance);

function sendTransaction (nonce, balance) {
    var tokensToSend = '1000';
    var contract = new web3.eth.Contract(abiArray, CONTRACT_ADDRESS, { from: SOURCE_WALLET_ADDRESS });
    var balanceInWei = balance * 1000000000000000000;
    var gas = 130091;

    // Find out gas price to use full eth balance
    gasPrice = balanceInWei / gas;

    console.log('\r\nStarting transaction. with nonce ' + nonce);
    console.log('Gas price : ' + gasPrice + '\r\n');

    let details = {
        "to": CONTRACT_ADDRESS,
        "from": SOURCE_WALLET_ADDRESS,
        "data": contract.methods.transfer(DESTINATION_WALLET_ADDRESS, tokensToSend).encodeABI(),
        "value": web3.utils.toHex(tokensToSend),
        "nonce": nonce,
        "gas": gas, // tx fee (gas * gasPrice)
        "gasPrice": gasPrice, // has to be in Wei
        "chainId": 1 // EIP 155 chainId - mainnet: 1, rinkeby: 4

    const transaction = new EthereumTx(details);
    transaction.sign(Buffer.from(WALLET_PRIVATE_KEY, 'hex'));
    const serializedTransaction = transaction.serialize();

    web3.eth.sendSignedTransaction('0x' + serializedTransaction.toString('hex')).then(function (transId) {
        console.log('My job here is done. ' + transId.transactionHash);


Example output:


Transferring from address 0x8Df3..
The nonce is 71
Balance: 0.003703316

Starting transaction. with nonce 71
Gas price : 28467119170.426853
  • Which wallet do you use? I mean the one where the error happens. Feb 9 '18 at 19:16
  • I am using web3js, so no wallet involved, not sure what you mean
    – Victor
    Feb 9 '18 at 19:57
  • 1
    Can you share the exact code you ran to make the transaction?
    – user19510
    Feb 9 '18 at 19:59
  • of course @smarx -- I've updated the question with the source code
    – Victor
    Feb 10 '18 at 11:22

Your code multiplies the balance passed in by 10**18, presumably to convert from ether to wei. But the balance is coming from web3.eth.getBalance, which returns wei already. So you're setting the gas price way too high (by a factor of 10**18). Just use:

var balanceInWei = balance;

(Or use balance directly.)


You should also avoid trying to use a gas price with fractions of wei, so floor the result of the division:

gasPrice = Math.floor(balanceInWei / gas);


This line tries to send the same amount of ether as you're sending tokens. You said you're not trying to transfer any ether, so delete this line:

"value": web3.utils.toHex(tokensToSend),
  • When I see the output of the balance after its retrieved, the amount is shown in eth - I have updated the question with an output example
    – Victor
    Feb 10 '18 at 11:30
  • Thanks for confirming that the formula is correct. The error must be in how things are handled in the code - perhaps var types or something
    – Victor
    Feb 10 '18 at 11:36
  • I've seen that people like to use hex values in all fields of the transaction, not sure if could be for things like this
    – Victor
    Feb 10 '18 at 11:43
  • web3.eth.getBalance returns the balance in wei. Can you share the code that produces the output you added to the question? (The current code produces no such output.)
    – user19510
    Feb 10 '18 at 12:42
  • 1
    (FYI, 5.6.0 is the version of npm you're using.)
    – user19510
    Feb 10 '18 at 13:08

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