Moment.js - how do I get the number of years since a date, not rounded up?

Question

I'm trying to calculate a person's age using Moment.js, but I'm finding that the otherwise useful fromNow method rounds up the years. For instance, if today is 12/27/2012 and the person's birth date is 02/26/1978, moment("02/26/1978", "MM/DD/YYYY").fromNow() returns '35 years ago'. How can I make Moment.js ignore the number of months, and simply return the number of years (i.e. 34) since the date?

Mallissa

Answer 1

I found that it would work to reset the month to January for both dates (the provided date and the present):

> moment("02/26/1978", "MM/DD/YYYY").month(0).from(moment().month(0))
"34 years ago"

Mallissa

In moment.js v2.3.1 there is a .fromNow() method which can also be helpful. – Phalarope

Answer 2

Using moment.js is as easy as:

var years = moment().diff('1981-01-01', 'years');
var days = moment().diff('1981-01-01', 'days');

For additional reference, you can read moment.js official documentation.

Petrinapetrine

If someone needs the number of years in float: var years = moment().diff('1981-01-01', 'years', true); // returns 40.43 – Alialia

Answer 3

http://jsfiddle.net/xR8t5/27/

if you do not want fraction values:

var years = moment().diff('1981-01-01', 'years',false);
alert( years);

if you want fraction values:

var years = moment().diff('1981-01-01', 'years',true);
alert( years);

Units can be [seconds, minutes, hours, days, weeks, months, years]

Absorbed

This technique is covered by @ebeltran's answer, and your discussion of fractional values has nothing to do with the question. I'd rather add it as a comment. – Mallissa

Answer 4

There appears to be a difference function that accepts time intervals to use as well as an option to not round the result. So, something like

Math.floor(moment(new Date()).diff(moment("02/26/1978","MM/DD/YYYY"),'years',true)))

I haven't tried this, and I'm not completely familiar with moment, but it seems like this should get what you want (without having to reset the month).

Uncloak

It appears you do not need to receive the floating point number from moment and then round it yourself, for this scenario. It looks like moment is correctly rounding the result for the year calculation using diff. – Chichi

From the docs, since 2.0.0, moment#diff will return number rounded down, so you only need to : age = moment().diff(birthDate, 'years') . – Joubert

Answer 5

This method is easy and powerful.

Value is a date and "DD-MM-YYYY" is the mask of the date.

moment().diff(moment(value, "DD-MM-YYYY"), 'years');

Caddric

Answer 6

Try this:

 moment("02/26/1978", "MM/DD/YYYY").fromNow().split(" ")[0];

Explanation:

We receive string something like this: '23 days ago'. Split it to array: ['23', 'days', 'ago'] and then take first item '23'.

Tonguelash

This post is being automatically flagged as low quality because it is only code. Would you mind expanding it by adding some text to explain how it solves the problem? – Geosphere

Answer 7

This method works for me. It's checking if the person has had their birthday this year and subtracts one year otherwise.

// date is the moment you're calculating the age of
var now = moment().unix();
var then = date.unix();
var diff = (now - then) / (60 * 60 * 24 * 365);
var years = Math.floor(diff);

Edit: First version didn't quite work perfectly. The updated one should

Culprit

This worked for me if i changed the days of the year to 365.25 to account for leap years – Stereoisomer

using 365.25 is an approximation that can end up in tears - type cal 1752 to see why – Sherlock

Answer 8

If you dont want to use any module for age calculation

var age = Math.floor((new Date() - new Date(date_of_birth)) / 1000 / 60 / 60 / 24 / 365.25)

Sot

Answer 9

When you want to show years and the remaining days:

var m = moment(d.birthday.date, "DD.MM.YYYY");
var years = moment().diff(m, 'years', false);
var days = moment().diff(m.add(years, 'years'), 'days', false);
alert(years + ' years, ' + days + ' days');

Boob

Answer 10

Get years and days using moment.js library

import moment from 'moment'

export function getAge(dateString: string) {
  const date = moment(dateString, 'YYYY-MM-DD')
  const years = moment().diff(date, 'years')
  const days = moment().diff(date.add(years, 'years'), 'days', false)
  return { years, days }
}

const birthDate = "1997-04-01T00:00:00.000Z";
const age = getAge(birthDate);

// Today is 2022-04-09
console.log({ age })
// Result: { age: { years: 25, days: 8 } }

Irritability

Answer 11

You can try this:

moment
.duration({
  years: moment(Date.now()).diff(datetime, "years", false),
})
.humanize()

Bombe

Answer 12

I prefer this small method.

function getAgeFromBirthday(birthday) {
    if(birthday){
      var totalMonths = moment().diff(birthday, 'months');
      var years = parseInt(totalMonths / 12);
      var months = totalMonths % 12;
        if(months !== 0){
           return parseFloat(years + '.' + months);
         }
    return years;
      }
    return null;
}

Chronometry

Exactly what I was looking for! – Charron

Be careful with string concatenation here. This will consider 11 months to be .11 of a year, i.e. Less than 9 months .9 – Jambeau

Answer 13

Here is the simple one using moment.js

let dt = dob;

        let age = '';

        let bY = Number(moment(dt).format('YYYY')); 
        let bM = Number(moment(dt).format('MM')); 
        let bD = Number(moment(dt).format('DD')); 

        let tY = Number(moment().format('YYYY')); 
        let tM = Number(moment().format('MM')); 
        let tD = Number(moment().format('DD')); 


        age += (tY - bY) + ' Y ';

        if (tM < bM) {
            age += (tM - bM + 12) + ' M ';
            tY = tY - 1;
        } else {
            age += (tM - bM) + ' M '
        }

        if (tD < bD) {
            age += (tD - bD + 30) + ' D ';
            tM = tM - 1;
        } else {
            age += (tD - bD) + ' D '
        }
        
        //AGE MONTH DAYS
        console.log(age);

Tinstone