Age Calculator using To display Years , Months , Days ?

You’re trying to build an Age Calculator (in C# or JavaScript?), and right now it’s only showing years, but you also want months and days to be calculated accurately.

Let’s cover both cases — C# (backend) and JavaScript (frontend) — since many people do this in either.

 Option 1: C# — Accurate Age in Years, Months, and Days

Here’s a clean method that gives exact years, months, and days between two dates:

using System;

public class Program
{
    public static void Main()
    {
        Console.Write("Enter your birthdate (yyyy-mm-dd): ");
        DateTime birthDate = DateTime.Parse(Console.ReadLine());
        DateTime today = DateTime.Today;

        int years = today.Year - birthDate.Year;
        int months = today.Month - birthDate.Month;
        int days = today.Day - birthDate.Day;

        // Adjust if current month/day is before birth month/day
        if (days < 0)
        {
            months--;
            DateTime prevMonth = today.AddMonths(-1);
            days += DateTime.DaysInMonth(prevMonth.Year, prevMonth.Month);
        }

        if (months < 0)
        {
            years--;
            months += 12;
        }

        Console.WriteLine($"Age: {years} years, {months} months, {days} days");
    }
}

 Example Output

If today is 2025-10-23 and birthdate is 2000-05-10,
it will print:

Age: 25 years, 5 months, 13 days

 Option 2: JavaScript (Web UI version)

If your age calculator runs in a web page:

  


  
Age Calculator
  
  Calculate
  


  

 Example Output

Age: 25 years, 5 months, 13 days

 Explanation

1. We first subtract years, months, and days separately.

2. If days < 0, it means the current day hasn’t reached the birth day yet in this month,
   so we borrow days from the previous month.

3. If months < 0, it means the current month hasn’t reached the birth month,
   so we borrow one year and add 12 months.

You can calculate age in Years, Months, and Days by comparing the birth date with today’s date. The logic is:

1. Subtract the birth year from the current year for the years.

2. If today’s month is less than the birth month, subtract 1 year and adjust the months.

3. Do the same for days if today’s day is less than the birth day, borrow days from the previous month.

Example:

• Birthdate: 2000-05-10

• Today: 2025-09-22

• Result → 25 Years, 4 Months, 12 Days

Most programming languages (like PHP, JavaScript, or Python) have built-in date functions to handle this calculation easily.

If you’d like to try it online, here’s a simple tool that does the calculation: Age Calculator