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Age ( birthday ; today ; format )

This calculation determines a person's age based upon their birthday and a given date.

  Average rating: 4.0 (40 votes) Log in to vote

Kevin Kurpe - Show more from this author

  Function definition: (Copy & paste into FileMaker's Edit Custom Function window)

Age ( birthday; today; format ) Let ( // This calculation determines a person's age based upon their birthday and a given date. // The result of this function can be displayed in four different formats:
// 1: Years
// 2: Years and Days
// 3: Years, Months and Days
// 4: Years ¶ Months ¶ Days [ // BEGIN the declaration of variables. //////////////////////////////////////////////////// // VARIABLES //////////////////////////////////////////////////// // BIRTHDAY Yb = Year ( birthday ) ; Mb = Month ( birthday ) ; DoMb = Day ( birthday ) ; DoYb = DayOfYear ( birthday ) ; // TODAY Yt = Year ( today ) ; Mt = Month ( today ) ; DoMt = Day ( today ) ; DoYt = DayOfYear ( today ) ; // LEAP YEAR FACTOR LYF = Case ( Mod ( Yt ; 400 ) = 0 ; 1 ; // 'century' years divisible by 400 are leap years Mod ( Yt ; 100 ) = 0 ; 1 ; // 'century' years not divisible by 400 are not leap years Mod ( Yt ; 4 ) = 0 ; 1 ; 0 ) ; // years divisible by 4 are leap years //////////////////////////////////////////////////// // CALCULATIONS //////////////////////////////////////////////////// Y = Yt - Yb - ( ( DoYt - LYF ) < DoYb ); M = Mod ( Mt - Mb + 12 - ( DoMt < DoMb ) ; 12 ) ; D1 = Abs ( today - Date ( Mt - ( DoMt < DoMb ) ; DoMb ; Yt ) ) ; D2 = Case ( ( DoYt - LYF ) ≥ DoYb ; // IF DoYt - LYF - DoYb ; // THEN DoYt + ( DayOfYear ( Date ( 12 ; 31 ; Yt ) - DoYb - LYF ) ) ) // ELSE ] ; // END the declaration of variables. //////////////////////////////////////////////////// // OUTPUT //////////////////////////////////////////////////// Case ( // Format 1: AGE IN YEARS format = 1 ; Y ; // Format 2: AGE IN YEARS AND DAYS format = 2 ; Y & " years and " & D2 & " days" ; // FORMAT 3: AGE IN YEARS, MONTHS AND DAYS format = 3 ; Y & " years and " & M & " months, and " & D1 & " days" ; // FORMAT 4: AGE IN YEARS, MONTHS AND DAYS (Carriage Return) format = 4 ; Y & " years¶" & M & " months¶" & D1 & " days" ) ) //////////////////////////////////////////////////// // CREDIT //////////////////////////////////////////////////// // ORIGINALLY AUTHORED BY // Chris Moyer // Bob Bowers // MODIFIED INTO A CUSTOM FUNCTION BY // Geoff Wells, DataIsland Software LLC // http://www.dataisland.com // REWORKED BY // Kevin Kurpe Click to copy

The function will calculate a persons age. The result of this function can be displayed in four different formats:

1: Years
2: Years and Days
3: Years, Months and Days.
4: Years ¶ Months ¶ Days



////////////////////////////////////////////////////
// CREDIT
////////////////////////////////////////////////////

// ORIGINALLY AUTHORED BY
// Chris Moyer
// Bob Bowers

// MODIFIED BY
// Geoff Wells, DataIsland Software LLC
// http://www.dataisland.com

// REWORKED BY
// Kevin Kurpe

 

Comments

		chopper, east hampton Aug 20, 2010
How is your function any different than this one http://www.briandunning.com/cf/57 ?

		Kevin Kurpe Aug 20, 2010
This is simply a reworking of that custom function. I added the contributions of Rob Wolf to fix an error with regard to the leap year. I reorganized the custom function in order to make modifying the output easier. Other than the fact that it's easier to read and manipulate, there is no difference. Enjoy!

		comment, VR Aug 22, 2010
This function returns incorrect results: A person born on Jan 31, 1982 is 27 years old on Jan 31, 2009; A year earlier, on Jan 31, 2008 the same person was 25 years old - TWO years younger. Not to mention that on Mar 1, 2011 this person will be "29 years and 1 months, and -2 days" old.

		Fritz Mills, Chicago, IL Sep 1, 2010
When I copy and paste and attempt to save, it stops with an error. Also I don't understand the use of "<" and "≥" in the variable calculations, as they seem to be used on one side of an "=" calculation rather than in place of an "=" sign.

		Gary Amstutz, Sweetwater Jan 2, 2011
DO NOT USE THIS FUNCTION! It is very error prone. If you look at the code, it ONLY looks at the two years (birth year and current year) to calculate the age, not accounting for which month of the year or day of the month the birthday is or the current date. So if the current day of the year is earlier than the day of the year of the birthdate, the age will be off by 1 year. It has other errors, too. Someone spent a lot of time formatting this, but didn't give the logic much thought. Don't use it.

		Gary Amstutz, Sweetwater Jan 2, 2011
ADDITIONAL NOTE: Use the one at http://www.briandunning.com/cf/57 I just tried it, and it calculates the age correctly. This one doesn't!

		Kevin Kurpe Jan 19, 2011
I updated this custom function to address an error related to how I was calculating "leap years". Thanks for the feedback Gary!

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