A decimal birthday is celebrated using the decimal (base ten) numeral system.
This form of celebration has become more popular since the widespread use of computers and the internet which have made the calculation of the decimal birthday easier to make.
Historically, in Korea it is common to celebrate the Bek-Il or the 100th day of life[1]. This tradition was born from a time of high infant mortality when many babies would die before three months of age. As a result the 100th day is a celebration of life as the baby has survived the difficult first 100 days of life.