How to calculate difference between two dates in hours?

Question

As I am new to javascript so I am asking this question how to find difference between two dates in hours.I am successfully calculated difference but when I give time in format of AM/PM it gives me output as NAN Please check my code I am posting below and thanks in advance:

function calculateTime() {
  var d2 = new Date('2018-02-12 03:00:00 AM');
  var d1 = new Date('2018-02-10 08:00:00 AM');
  var seconds =  (d2- d1)/1000;
  var hours = seconds/3600;
  console.log(hours);
}
calculateTime();

Works for me https://jsfiddle.net/u7krsbqr/ also, this is not jQuery, this is Javascript — CertainPerformance, Apr 21 '18 at 05:43
If your code gives you NaN, then you aren't using the same code you posted here. The code you pasted here works - see the fiddle. — CertainPerformance, Apr 21 '18 at 05:47

score 2 · Answer 1 · answered Apr 21 '18 at 05:49

2

Simply subtract the date objects from one another.

var hours = Math.abs(date1 - date2) / 36e5;

The subtraction returns the difference between the two dates in milliseconds. 36e5 is short for 60*60*1000 and so dividing by 36e5 will give you hours.

answered Apr 21 '18 at 05:49

Joshua

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it is giving me hours when i remove AM from date but i want time in AM/PM format – user7596840 Apr 21 '18 at 05:53
That's essentially what the OP is doing. The issue is incorrectly parsing to Date initially. – RobG Apr 21 '18 at 07:27

Eddie · Accepted Answer · 2018-04-21T07:38:08.017

1

Firefox will return Invalid date for the format YYYY-MM-DD HH:MM:SS AM

One option is to use year, month, day separately on new Date()

new Date(year, month [, day [, hours [, minutes [, seconds [, milliseconds]]]]]);

Like:

function calculateTime() {
  var formatDate = function(dt) {
    let n = dt.split(/\D/).splice(0,6);
    n[3] = dt.slice(-2) === 'PM' ? ( +n[3] + 12 ) : n[3]; //Update Hour
    n[1] = n[1] - 1; //Update month
    return n;
  }

  var d2 = new Date(...formatDate('2018-02-12 03:00:00 AM'));
  var d1 = new Date(...formatDate('2018-02-10 08:00:00 AM'));

  var seconds = (d2 - d1) / 1000;

  var hours = seconds / 3600;
  console.log(hours);
}

calculateTime();

Doc: new Date

edited Apr 21 '18 at 07:38

answered Apr 21 '18 at 05:55

Eddie

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A lot simpler to just use `dt.split(/\D/)`. Also, *h* is a string so `h + 12` will do concatenation, not addition, `+h + 12` will fix that. – RobG Apr 21 '18 at 07:22
Good idea. Thanks @RobG – Eddie Apr 21 '18 at 07:39

How to calculate difference between two dates in hours?

2 Answers2