Calculating Length of Service from days to Years/Months/Days

Hi again Kristin_Lyons, more than a formula you need and algorithm. In C#:

using System;
					
public class Program
{
	public static void Main()
	{
		var startDate = new DateTime(2012, 5, 21);
		var totalDays = 2102;
		var span = GetDateTimeSpan(startDate, totalDays);
		
		Console.WriteLine($"Years: {span.Years}");
		Console.WriteLine($"Months: {span.Months}");
		Console.WriteLine($"Days: {span.Days}");
	}
	
	public static (int Years, int Months, int Days) GetDateTimeSpan(DateTime startDate, int totalDays)
	{
		int years = 0;
		int months = 0;
		int days = 0;

		var endDate = startDate.AddDays(totalDays);
		var currentDate = endDate;

		// If totalDays is negative, swap dates
		if (startDate > endDate)
		{
			endDate = startDate;
			startDate = currentDate;
		}

		// Count years
		currentDate = startDate;
		while (currentDate.AddYears(years + 1) <= endDate)
		{
			years++;
		}

		// Count months
		currentDate = currentDate.AddYears(years);
		while (currentDate.AddMonths(months + 1) <= endDate)
		{
			months++;
		}

		// Count days
		currentDate = currentDate.AddMonths(months);
		while (currentDate.AddDays(days + 1) <= endDate)
		{
			days++;
		}

		return (years, months, days);
	}
}

You can play with it at https://dotnetfiddle.net/. Be sure that you choose the following options:

• Language: C#
• Project type: Console
• Compiler: .NET 8

Replace all the code, and you got it.

Regards,

Miguel.