How does Google know when it is my birthday? While you are creating a new Gmail - Google account, you fill the details of your birthday. This way, Google know when it's your birthday.

You may need to get a court order issued by a judge before the vital records office will change your date of birth. In most cases, the date on a legally-issued birth certificate is presumed to be correct.

Google Search is a powerful tool to find someone's birthday. Here's how you can use it effectively: Start with a simple search by entering the person's full name followed by the word “birthday”. Look through the first few pages of results; sometimes, personal websites or past event listings may mention birthdays.