Add the numbers of the month and day of your birthday together. For example, if your birthday is on March 23, or 3/23, then you would add 3, 2 and 3 together, obtaining 8.
Add the numbers of today's date together. For the example, if today's date is September 28, or 9/28, you would add 9, 2 and 8 together, obtaining the sum of 19.
Add the sum of your birthday numbers to the sum of today's numbers. For the example, you would add 8 to 19 to obtain 27.
Add the numbers of the current year together. For the example, if the year is 2010, adding 2, 0, 1, and 0 together obtains 3 as the sum.
Add the sum of the numbers of the current year to the combined sum of birthday numbers and today's numbers. For the example, you would add 27 and 3 to obtain the sum of 30.
Add the numbers from the sum of the combined current year, day and birthday numbers together. For the example, you would add 3 and 0 together, obtaining 3. This is your personal day.