Calculate a person's age

Question

Does anyone have an elegant, accurate way of calculating a person's age given today's date and time and the person's date of birth date?

Answer 1

Use the TimeSpan Structure to achieve what you want. You can extract days, minutes or even years. Check out the example in MSDN. GL HTH

---

William Wegerson (www.OmegaCoder.Com)

Answer 2

TimeSpan won't do it.  There's no property for Years.

Here's a couple of ways:

1. Use a while loop

int age = 0;
while (DateTime.Today.AddYears(-(i + 1)) >= birthDay)
    age++;

2. Use another more detailed method:

//// get the raw years
DateTime birthDay = new DateTime(1979, 11, 4);
var age = DateTime.Today.Year - birthDay.Year;

// adjust for whether the birthday is past or not.
DateTime thisYearsBirthDay = new DateTime(DateTime.Today.Year, birthDay.Month, birthDay.Day);
age -= DateTime.Today >= thisYearsBirthDay ? 0 : 1;

Console.WriteLine(age);

---

Coding Light - Illuminated Ideas and Algorithms in Software
Coding Light Wiki • LinkedIn • ForumsBrowser

Answer 3

David is right that timespan doesn't give years...but that is a simple calculation Days/365. :-)

---

William Wegerson (www.OmegaCoder.Com)

Answer 4

Don't forget leap years Omega. The DateTime method is a lot easier if you want to be accurate.

Answer 5

Hi,

You can use the following class also.

    class Age
    {
        public Age(DateTime dateOfBirth)
        {
            CalculateAge(dateOfBirth,DateTime.Now);
        }
        public Age(DateTime dateOfBirth, DateTime dateToSubstractFrom)
        {
            CalculateAge(dateOfBirth, dateToSubstractFrom);
        }
        public int Year { get; set; }
        public int Month { get; set; }
        public int Day { get; set; }
        public int Hour { get; set; }
        public int Minute { get; set; }
        public int Second { get; set; }
        private void ClearValue()
        {
            Year = 0;
            Month = 0;
            Day = 0;
            Hour = 0;
            Minute = 0;
            Second = 0;
        }
        private void CalculateAge(DateTime dateOfBirth,DateTime dateToSubstractFrom)
        {
            ClearValue();
            DateTime internalDateOfBirth = dateOfBirth;
            while (internalDateOfBirth.AddYears(1) <= dateToSubstractFrom)
            {
                this.Year++;
                internalDateOfBirth = internalDateOfBirth.AddYears(1);
            }
            while (internalDateOfBirth.AddMonths(1) <= dateToSubstractFrom)
            {
                this.Month++;
                internalDateOfBirth = internalDateOfBirth.AddMonths(1);
            }
            while (internalDateOfBirth.AddDays(1) <= dateToSubstractFrom)
            {
                this.Day++;
                internalDateOfBirth = internalDateOfBirth.AddDays(1);
            }
            while (internalDateOfBirth.AddHours(1) <= dateToSubstractFrom)
            {
                this.Hour++;
                internalDateOfBirth = internalDateOfBirth.AddHours(1);
            }
            while (internalDateOfBirth.AddMinutes(1) <= dateToSubstractFrom)
            {
                this.Minute++;
                internalDateOfBirth = internalDateOfBirth.AddMinutes(1);
            }
            while (internalDateOfBirth.AddSeconds(1) <= dateToSubstractFrom)
            {
                this.Second++;
                internalDateOfBirth = internalDateOfBirth.AddSeconds(1);
            }
        }
    }