Javascript VS PHP rounding

Question

I am having some problems with the way PHP and javascript round numbers. I am using PHP's round function and this javascript function:

function roundNumber(number, decimals) {     
    var newnumber = new Number(number+'').toFixed(parseInt(decimals));
    var value = parseFloat(newnumber);
    return value;
}

The number i am trying to round is 43.65 * 2.5 + 40% which when done using a calculator = 152.775 or when rounded in PHP = 152.78.

In javascript when i do a console.log the number is 152.774999999998 and when rounded with the above function gives me 152.77

Any help to reslove this issue is greatly appreciated

Answer 1

This isn't anything to do with rounding per se, but is to do with how decimal numbers are represented in binary-based hardware.

Check out the floating point guide for lots more information on this, as well as solutions/alternatives.