C# – How to calculate someone’s age based on a DateTime type birthday

cdatetimenet

Given a DateTime representing a person's birthday, how do I calculate their age in years?

Best Answer

An easy to understand and simple solution.

// Save today's date.
var today = DateTime.Today;

// Calculate the age.
var age = today.Year - birthdate.Year;

// Go back to the year in which the person was born in case of a leap year
if (birthdate.Date > today.AddYears(-age)) age--;

However, this assumes you are looking for the western idea of the age and not using East Asian reckoning.

Related Solutions

Sql – How to return only the Date from a SQL Server DateTime datatype

SELECT DATEADD(dd, 0, DATEDIFF(dd, 0, @your_date))

for example

SELECT DATEADD(dd, 0, DATEDIFF(dd, 0, GETDATE()))

gives me

2008-09-22 00:00:00.000

Pros:

No varchar<->datetime conversions required
No need to think about locale

C# – Given a DateTime object, how to get an ISO 8601 date in string format

Note to readers: Several commenters have pointed out some problems in this answer (related particularly to the first suggestion). Refer to the comments section for more information.

DateTime.UtcNow.ToString("yyyy-MM-ddTHH\\:mm\\:ss.fffffffzzz");

Using custom date-time formatting, this gives you a date similar to
2008-09-22T13:57:31.2311892-04:00.

Another way is:

DateTime.UtcNow.ToString("o");

which uses the standard "round-trip" style (ISO 8601) to give you
2008-09-22T14:01:54.9571247Z.

To get the specified format, you can use:

DateTime.UtcNow.ToString("yyyy-MM-ddTHH:mm:ssZ")

Best Answer

Related Solutions

Sql – How to return only the Date from a SQL Server DateTime datatype

C# – Given a DateTime object, how to get an ISO 8601 date in string format

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