Calculate percentage Javascript

It seems working :

HTML :

 <input type='text' id="pointspossible"/>
<input type='text' id="pointsgiven" />
<input type='text' id="pointsperc" disabled/>

JavaScript :

    $(function(){

    $('#pointspossible').on('input', function() {
      calculate();
    });
    $('#pointsgiven').on('input', function() {
     calculate();
    });
    function calculate(){
        var pPos = parseInt($('#pointspossible').val()); 
        var pEarned = parseInt($('#pointsgiven').val());
        var perc="";
        if(isNaN(pPos) || isNaN(pEarned)){
            perc=" ";
           }else{
           perc = ((pEarned/pPos) * 100).toFixed(3);
           }

        $('#pointsperc').val(perc);
    }

});

Demo : http://jsfiddle.net/vikashvverma/1khs8sj7/1/

Try:

const result = Math.round((data.expense / data.income) * 100)

You can use this

function percentage(partialValue, totalValue) {
   return (100 * partialValue) / totalValue;
} 

Example to calculate the percentage of a course progress base in their activities.

const totalActivities = 10;
const doneActivities = 2;

percentage(doneActivities, totalActivities) // Will return 20 that is 20%