Each item was associated with a prediction. For example, a person finding a gold coin in a birthday cake would supposedly become wealthy; a person discovering a thimble would never marry. Sometimes special candles are substituted for the many individual candles in the shape of a numeral. For example, on the first birthday, there may be one candle on the cake in the shape of the numeral one, and on the tenth birthday there may be two candles on the cake, one in the shape of the numeral one followed by the other in the shape of the number zero.

In addition to parties, it is common for people to receive gifts on their birthdays or surprise parties. The popular gifts include toys, books, jewellery, clothes, flowers, technical devices, etc. However, sometimes it is expected of the person celebrating their birthday to treat their party guests instead; this varies depending on the local culture and may involve party gifts or other gestures, for example inviting to the restaurant or bar (some of them offer special birthday programs), arranging party at home, or at work. The origin of the birthday gift giving originates from the gift giving celebration of Christmas.

A birthday, as the term implies, is the anniversary of the particular day on which a person was born. Though by no means universal, such occasions are celebrated in numerous cultures, often with a party or, in some instances, a rite of passage. "Happy Birthday to You", also known more simply as "Happy Birthday", is a traditional song that is sung to celebrate the anniversary of a person's birth. According to the 1998 Guinness Book of World Records, "Happy Birthday to You" is the most recognized song in the English language, followed by "For He's a Jolly Good Fellow" and "Auld Lang Syne". The song's base lyrics have been translated into at least 18 languages.