How do I calculate a person's age in months/years?

Question

How do I calculate a person's age in months/years such that anyone under two years old is reported in months and 2+ years in years only?

Yeah, I thought this looked trivial but it's surprisingly not as straight forward as you would expect. — Brad, Nov 13 '12 at 02:55
@JohanLarsson, that doesn't answer the question of months. And if you read the comments, you see that the #1 answer isn't even right for just years. — Jonathan Allen, Nov 13 '12 at 03:29

L.B · Accepted Answer · 2012-11-13T07:05:32.227

3

I would use NodaTime for this:

var d1 = new NodaTime.LocalDate(1997, 12, 10);
var d2 = new NodaTime.LocalDate(2012, 11, 13);

var period = NodaTime.Period.Between(d1, d2);
var m = period.Months;
var y = period.Years;

edited Nov 13 '12 at 07:05

answered Nov 13 '12 at 06:59

L.B

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score 0 · Answer 2 · edited Nov 13 '12 at 01:39

0

var now = DateTime.Today;

int months = 0;
while (true)
{
    var temp = dob.AddMonths((int)months);
    if (now < temp)
    {
        if (now.Day < temp.Day)
            months--; //accounts for short months
        break;
    }
    months++;
}

if (months < 24)
    return (months + " months");
else
    return (Math.Floor( (decimal)months / 12.0M) + " years");

edited Nov 13 '12 at 01:39

jonvuri

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answered Nov 13 '12 at 01:22

Jonathan Allen

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Was this meant to be the code that you've already tried? If so, you should have included it in your question. – jonvuri Nov 13 '12 at 01:24
1

@Kiyura : Really? Suggest you read the following post: http://blog.stackoverflow.com/2011/07/its-ok-to-ask-and-answer-your-own-questions/ – spender Nov 13 '12 at 01:29
@spender, I am quite aware, I just wanted to be sure he wasn't making a mistake. I probably should have taken a gander at his rep first. :) – jonvuri Nov 13 '12 at 01:32
Trying wiki-style with THIS question? Oh dear, really? – walther Nov 13 '12 at 01:49
I'm looking for a better solution that doesn't involve a loop. – Jonathan Allen Nov 13 '12 at 03:27

score 0 · Answer 3 · edited May 23 '17 at 12:14

0

I've literally lost an hour+ to this challenge, I thought it would be simple. Have found this answer on another SO question which may be useful

C# Formatting Age - Regarding Days, Weeks , Months - Years

edited May 23 '17 at 12:14

Community

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answered Nov 13 '12 at 02:39

NoPyGod

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That works for the US, but not for other countries. "Several countries have skipped dates after the birth of current living people, including Russia (1918), Greece (1924) and Turkey (1926)." – Lars D Nov 9 '09 – Jonathan Allen Nov 13 '12 at 03:30
Yeah it's a complicated problem, you may wish to find a library to do it for you if it's very important to have accurate figures. – NoPyGod Nov 13 '12 at 03:32

Brad · Answer 4 · 2012-11-13T16:39:28.550

-1

private string Birthdate(DateTime birthday)
{
    var birthdayTicks = birthday.Ticks;
    var twoYearsTicks = birthday.AddYears(2).Ticks;
    var NowTicks = DateTime.Now.Ticks;

    var moreThanTwoYearsOld = twoYearsTicks < NowTicks;

    var age = new DateTime(DateTime.Now.Subtract(birthday).Ticks);

    return moreThanTwoYearsOld ? (age.Year-1).ToString() + " years" : (age.Year-1 >= 1 ? age.Month + 12 : age.Month).ToString() + " months";
}

edited Nov 13 '12 at 16:39

answered Nov 13 '12 at 02:30

Brad

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That almost never gives the right answer. Then length of a year is not 365.25, nor is a month 1/12th of a year. – Jonathan Allen Nov 13 '12 at 03:34
Why is the length of a year *not* 365.25? – Brad Nov 13 '12 at 12:15
@JonathanAllen phew! How about that one? – Brad Nov 13 '12 at 16:24

How do I calculate a person's age in months/years?

4 Answers4