Difference in Months between two dates in JavaScri

Question

How would I work out the difference for two Date() objects in JavaScript, while only return the number of months in the difference?

Any help would be great :)

Answer 1

Consider each date in terms of months, then subtract to find the difference.

var past_date = new Date('11/1/2014');
var current_date = new Date();

var difference = (current_date.getFullYear()*12 + current_date.getMonth()) - (past_date.getFullYear()*12 + past_date.getMonth());

This will get you the difference of months between the two dates, ignoring the days.

Answer 2

Sometimes you may want to get just the quantity of the months between two dates totally ignoring the day part. So for instance, if you had two dates- 2013/06/21 and 2013/10/18- and you only cared about the 2013/06 and 2013/10 parts, here are the scenarios and possible solutions:

var date1=new Date(2013,5,21);//Remember, months are 0 based in JS
var date2=new Date(2013,9,18);
var year1=date1.getFullYear();
var year2=date2.getFullYear();
var month1=date1.getMonth();
var month2=date2.getMonth();
if(month1===0){ //Have to take into account
  month1++;
  month2++;
}
var numberOfMonths; 

1.If you want just the number of the months between the two dates excluding both month1 and month2

numberOfMonths = (year2 - year1) * 12 + (month2 - month1) - 1;

2.If you want to include either of the months

numberOfMonths = (year2 - year1) * 12 + (month2 - month1);

3.If you want to include both of the months

numberOfMonths = (year2 - year1) * 12 + (month2 - month1) + 1;

Answer 3

function calcualteMonthYr(){
    var fromDate =new Date($('#txtDurationFrom2').val()); //date picker (text fields)
    var toDate = new Date($('#txtDurationTo2').val());

var months=0;
        months = (toDate.getFullYear() - fromDate.getFullYear()) * 12;
        months -= fromDate.getMonth();
        months += toDate.getMonth();
            if (toDate.getDate() < fromDate.getDate()){
                months--;
            }
    $('#txtTimePeriod2').val(months);
}

Answer 4

Difference in Months between two dates in JavaScript:

 start_date = new Date(year, month, day); //Create start date object by passing appropiate argument
 end_date = new Date(new Date(year, month, day)

total months between start_date and end_date :

 total_months = (end_date.getFullYear() - start_date.getFullYear())*12 + (end_date.getMonth() - start_date.getMonth())

Answer 5

Following code returns full months between two dates by taking nr of days of partial months into account as well.

var monthDiff = function(d1, d2) {
  if( d2 < d1 ) { 
    var dTmp = d2;
    d2 = d1;
    d1 = dTmp;
  }

  var months = (d2.getFullYear() - d1.getFullYear()) * 12;
  months -= d1.getMonth() + 1;
  months += d2.getMonth();

  if( d1.getDate() <= d2.getDate() ) months += 1;

  return months;
}

monthDiff(new Date(2015, 01, 20), new Date(2015, 02, 20))
> 1

monthDiff(new Date(2015, 01, 20), new Date(2015, 02, 19))
> 0

monthDiff(new Date(2015, 01, 20), new Date(2015, 01, 22))
> 0

Answer 6

See what I use:

function monthDiff() {
    var startdate = Date.parseExact($("#startingDate").val(), "dd/MM/yyyy");
    var enddate = Date.parseExact($("#endingDate").val(), "dd/MM/yyyy");
    var months = 0;
    while (startdate < enddate) {
        if (startdate.getMonth() === 1 && startdate.getDate() === 28) {
            months++;
            startdate.addMonths(1);
            startdate.addDays(2);
        } else {
            months++;
            startdate.addMonths(1);
        }
    }
    return months;
}