First under my calendars on the left hand side, make sure there's a check mark next to your birthdays calendar.

Now go to contacts dot google dot com and select contacts from the left hand side.

Click, create a contact and then create a contact again from the drop down.

Mhm.

A pop up window will appear.

Type the name of the person whose birthday it is and other details.

If you wish.

Click show more and scroll down to find birthday at their date of birth and then click Save yeah, mhm Back in Google calendar, refresh your Web page and you'll see the birthday appear in your calendar.