January 1 is Samad Alawi's birthday. It's also the birthday of his wife, his two sons, 32 of his friends and thousands of other Afghans -- a date chosen for convenience by a generation who do not know when they were born.
In the absence of birth certificates or official records, many Afghans have long used the seasons or historical events to help determine their age.
But the explosion of social media networks such as Facebook, which require users to register their birthday, and the growing demand for passports and visas have forced Afghans to pick a day -- any day.
January 1 has become a common choice, although the date is more about practicality than parties.
"It seemed all Afghans had birthdays on January 1," Samad Alawi, who is 43, said.
Even those who know their real birth date often choose January 1 because they do not want the hassle of converting their birthday from the Solar Hijri, an Islamic calendar used only in Afghanistan and Iran.
The first day of the year in Hijri usually corresponds to March 21.
"When I first created my Facebook account in 2014 it was just easier to choose January 1 as my birthday from the drop down list," Alawi told AFP.
"The internet was also slow and it was difficult to convert the date to a Western calendar."
Even the official identity card, or Tazkira, held by most Afghans offers little official clarity, with a person's age "determined based on physical appearance".
"My Tazkira says I was three years old in 1365 in the Hijri calendar (1986). That is the year my Tazkira was issued," Abdul Hadi, who is now 34, told AFP.
"There is no blank space for a date of birth in an Afghan Tazkira. How can you remember your date of birth if you don't have one on the record?"
Authorities are trying to change that.
In recent years Afghan hospitals in major cities have started issuing newborn babies with birth certificates -- something previous generations lack.
The government also plans to issue e-Tazkiras, or computerised national ID cards, to Afghans which would include their date of birth, if it is known. But the process has been stalled for years by political and technical problems.
In the absence of official records, some educated parents resort to recording their children's birthdays on slips of paper which are often kept in a copy of the Koran.
"I hope one day all Afghans have their proper date of births so that social media doesn't have to tell them how old they are," Alawi said.