Difference between two dates in years, months, days in JavaScript

I've been searching for 4 hours now, and have not found a solution to get the difference between two dates in years, months, and days in JavaScript, like: 10th of April 2010 was 3 years, x month and y days ago.

There are lots of solutions, but they only offer the difference in the format of either days OR months OR years, or they are not correct (meaning not taking care of actual number of days in a month or leap years, etc). Is it really that difficult to do that?

I've had a look at:

http://momentjs.com/ -> can only output the difference in either years, months, OR days
http://www.javascriptkit.com/javatutors/datedifference.shtml
http://www.javascriptkit.com/jsref/date.shtml
http://timeago.yarp.com/
www.stackoverflow.com -> Search function

In php it is easy, but unfortunately I can only use client-side script on that project. Any library or framework that can do it would be fine, too.

Here are a list of expected outputs for date differences:

//Expected output should be: "1 year, 5 months".
diffDate(new Date('2014-05-10'), new Date('2015-10-10'));

//Expected output should be: "1 year, 4 months, 29 days".
diffDate(new Date('2014-05-10'), new Date('2015-10-09'));

//Expected output should be: "1 year, 3 months, 30 days".
diffDate(new Date('2014-05-10'), new Date('2015-09-09'));

//Expected output should be: "9 months, 27 days".
diffDate(new Date('2014-05-10'), new Date('2015-03-09'));

//Expected output should be: "1 year, 9 months, 28 days".
diffDate(new Date('2014-05-10'), new Date('2016-03-09'));

//Expected output should be: "1 year, 10 months, 1 days".
diffDate(new Date('2014-05-10'), new Date('2016-03-11'));

How precise do you need to be? If you do need to take into account common years and leap years, and the exact difference in days between months then you'll have to write something more advanced but for a basic and rough calculation this should do the trick:

today = new Date()
past = new Date(2010,05,01) // remember this is equivalent to 06 01 2010
//dates in js are counted from 0, so 05 is june

function calcDate(date1,date2) {
    var diff = Math.floor(date1.getTime() - date2.getTime());
    var day = 1000 * 60 * 60 * 24;

    var days = Math.floor(diff/day);
    var months = Math.floor(days/31);
    var years = Math.floor(months/12);

    var message = date2.toDateString();
    message += " was "
    message += days + " days " 
    message += months + " months "
    message += years + " years ago \n"

    return message
    }


a = calcDate(today,past)
console.log(a) // returns Tue Jun 01 2010 was 1143 days 36 months 3 years ago

Keep in mind that this is imprecise, in order to calculate the date with full precision one would have to have a calendar and know if a year is a leap year or not, also the way I'm calculating the number of months is only approximate.

But you can improve it easily.

Actually, there's a solution with a moment.js plugin and it's very easy.

You might use moment.js

Don't reinvent the wheel again.

Just plug Moment.js Date Range Plugin.

Example:

var starts = moment('2014-02-03 12:53:12');
var ends   = moment();

var duration = moment.duration(ends.diff(starts));

// with ###moment precise date range plugin###
// it will tell you the difference in human terms

var diff = moment.preciseDiff(starts, ends, true); 
// example: { "years": 2, "months": 7, "days": 0, "hours": 6, "minutes": 29, "seconds": 17, "firstDateWasLater":  false }


// or as string:
var diffHuman = moment.preciseDiff(starts, ends);
// example: 2 years 7 months 6 hours 29 minutes 17 seconds

document.getElementById('output1').innerHTML = JSON.stringify(diff)
document.getElementById('output2').innerHTML = diffHuman

<html>
<head>

  <script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.14.1/moment.min.js"></script>

  <script src="https://raw.githubusercontent.com/codebox/moment-precise-range/master/moment-precise-range.js"></script>

</head>
<body>
  
  <h2>Difference between "NOW and 2014-02-03 12:53:12"</h2>
  <span id="output1"></span>
  <br />
  <span id="output2"></span>
  
</body>
</html>

Modified this to be a lot more accurate. It will convert dates to a 'YYYY-MM-DD' format, ignoring HH:MM:SS, and takes an optional endDate or uses the current date, and doesn't care about the order of the values.

function dateDiff(startingDate, endingDate) {
    var startDate = new Date(new Date(startingDate).toISOString().substr(0, 10));
    if (!endingDate) {
        endingDate = new Date().toISOString().substr(0, 10);    // need date in YYYY-MM-DD format
    }
    var endDate = new Date(endingDate);
    if (startDate > endDate) {
        var swap = startDate;
        startDate = endDate;
        endDate = swap;
    }
    var startYear = startDate.getFullYear();
    var february = (startYear % 4 === 0 && startYear % 100 !== 0) || startYear % 400 === 0 ? 29 : 28;
    var daysInMonth = [31, february, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];

    var yearDiff = endDate.getFullYear() - startYear;
    var monthDiff = endDate.getMonth() - startDate.getMonth();
    if (monthDiff < 0) {
        yearDiff--;
        monthDiff += 12;
    }
    var dayDiff = endDate.getDate() - startDate.getDate();
    if (dayDiff < 0) {
        if (monthDiff > 0) {
            monthDiff--;
        } else {
            yearDiff--;
            monthDiff = 11;
        }
        dayDiff += daysInMonth[startDate.getMonth()];
    }

    return yearDiff + 'Y ' + monthDiff + 'M ' + dayDiff + 'D';
}

Then you can use it like this:

// based on a current date of 2019-05-10
dateDiff('2019-05-10'); // 0Y 0M 0D
dateDiff('2019-05-09'); // 0Y 0M 1D
dateDiff('2018-05-09'); // 1Y 0M 1D
dateDiff('2018-05-18'); // 0Y 11M 23D
dateDiff('2019-01-09'); // 0Y 4M 1D
dateDiff('2019-02-10'); // 0Y 3M 0D
dateDiff('2019-02-11'); // 0Y 2M 27D
dateDiff('2016-02-11'); // 3Y 2M 28D - leap year
dateDiff('1972-11-30'); // 46Y 5M 10D
dateDiff('2016-02-11', '2017-02-11'); // 1Y 0M 0D
dateDiff('2016-02-11', '2016-03-10'); // 0Y 0M 28D - leap year
dateDiff('2100-02-11', '2100-03-10'); // 0Y 0M 27D - not a leap year
dateDiff('2017-02-11', '2016-02-11'); // 1Y 0M 0D - swapped dates to return correct result
dateDiff(new Date() - 1000 * 60 * 60 * 24); // 0Y 0M 1D

Older less accurate but simpler version

@RajeevPNadig's answer was what I was looking for, but his code returns incorrect values as written. This is not very accurate because it assumes that the sequence of dates from 1 January 1970 is the same as any other sequence of the same number of days. E.g. it calculates the difference from 1 July to 1 September (62 days) as 0Y 2M 3D and not 0Y 2M 0D because 1 Jan 1970 plus 62 days is 3 March.

// startDate must be a date string
function dateAgo(date) {
    var startDate = new Date(date);
    var diffDate = new Date(new Date() - startDate);
    return ((diffDate.toISOString().slice(0, 4) - 1970) + "Y " +
        diffDate.getMonth() + "M " + (diffDate.getDate()-1) + "D");
}

Then you can use it like this:

// based on a current date of 2018-03-09
dateAgo('1972-11-30'); // "45Y 3M 9D"
dateAgo('2017-03-09'); // "1Y 0M 0D"
dateAgo('2018-01-09'); // "0Y 2M 0D"
dateAgo('2018-02-09'); // "0Y 0M 28D" -- a little odd, but not wrong
dateAgo('2018-02-01'); // "0Y 1M 5D" -- definitely "feels" wrong
dateAgo('2018-03-09'); // "0Y 0M 0D"

If your use case is just date strings, then this works okay if you just want a quick and dirty 4 liner.

I used this simple code to get difference in Years, Months, days with current date.

var sdt = new Date('1972-11-30');
var difdt = new Date(new Date() - sdt);
alert((difdt.toISOString().slice(0, 4) - 1970) + "Y " + (difdt.getMonth()+1) + "M " + difdt.getDate() + "D");

Difference between two dates in years, months, days in JavaScript

You might use moment.js

Example:

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