Can I calculate my age manually?

Yes, you can calculate your age manually by subtracting your birth year from the current year. If your birthday hasn't occurred yet in the current year, subtract one additional year.

How do you calculate age in months and days manually?

To find months and days, you compare the birth date and current date. If the current day is less than the birth day, you 'borrow' 30 days from the month column to complete the subtraction.