Web3.js – How to Interpret Result of web3.eth.getBalance

If your token have 18 decimals

like an ether you can use

then(function(balance) {
    console.log(web3.fromWei(balance.toNumber(), "ether" ) );
})

Use fromWei to convert your bigNumber to ether and then convert it to Number. Be aware that unnecessary 0 after the floating point will not be displayed.

In web3 ^1.0 it may change to web3.utils.fromWei instead of web3.fromWei doc. Note that truffle ^5.0 uses web3 ^1.0.

If you have a different token decimal

Let's say 6. You'll have to do the conversion manually with something like:

var tokenBalance = balance.ToNumber() / Math.pow(10, tokenDecimals)

I wrote a simple Web3.js sample which fetches the balance of an Ethereum address: https://github.com/shawntabrizi/ETH-Balance

This is using Web3.js 0.2x.x, but the only difference here for Web3.js 1.0 is to change web3.fromWei to web3.utils.fromWei.

Thus by simply making that one small change, you can get the call to start working:

web3.eth.getBalance(address, function (error, wei) {
    if (!error) {
        var balance = web3.utils.fromWei(wei, 'ether');
        console.log(balance + " ETH");
    }
});

You can also read my blog post which discusses how to make Web3.js work asynchronously with JavaScript Promises.