Programmer's Day

The number behind it

Software is built on the byte, a small unit that can stand for 256 different values. That is where the date comes from. The 256th day of the year was picked because programmers know the number at once, and because it can be written as 100 in hexadecimal. It is also the largest power of two that still fits inside a year, whether that year runs to 365 days or 366, so the date lands in the middle of September.

From petition to decree

In 2002 two employees of a software company, Valentin Balt and Michael Cherviakov, began collecting signatures. Their aim was to persuade the Russian government to give the day official standing. Seven years later, on 24 July 2009, a government ministry responsible for communications and the media put out a draft order creating a new public holiday for programmers. On 11 September 2009 President Dmitry Medvedev signed the decree that made it real.

The date in China

In China the day is kept on 24 October, and it has been established there for many years. The figures for that date can be read as 1024, which is 2 to the power of ten, and 1024 is the number behind the binary prefix kibi, written Ki. Because the date is fixed by the month and day rather than counted out from the start of the year, it does not move when a leap day appears.

Days for other trades

The infobox for this day links it to Engineer's Day, another observance for a working trade. Lists that accompany the article also point to Pi Day and Tau Day, which rest on numbers in much the same spirit, and to System Administrator Appreciation Day, Secretary's Day and World Information Society Day. These days are grouped together in the article's lists. The sources describe no shared ceremony between them, and each stands on its own.

How Programmer's Day is kept

The day belongs to programmers, and it is the trade rather than a family or a congregation that keeps it. There is no set ritual in the sources. What people share is the date itself, and in Russia it carries the weight of an official public holiday, created by a decree signed in 2009 after a petition that began seven years earlier. The infobox calls it an international day observed worldwide, with no fixed programme recorded, and it is often mentioned beside Engineer's Day.

When and where

The date is set by counting days rather than by the calendar month. It is the 256th day of the year, which lands on 13 September in an ordinary year and on 12 September in a leap year. In Russia that is the date used. China keeps it on 24 October instead.

The day's recorded country of origin is Ukraine. Russia is where it holds official standing, after the 2009 decree, and China keeps a separate date, 24 October. In 2024, a leap year, the Russian date fell on 12 September, and in 2025 it falls on 13 September.

What Programmer's Day means

For programmers the date is a shared reference that everyone in the trade can read: 256 is the number of values a single byte can hold, and the same value in hexadecimal is 100. Choosing it says that the people who write software have a language and a set of jokes of their own. The day also names that shared work in public, which in Russia led all the way to a decree.

Questions people ask about Programmer's Day

See also

Arbor DayAn annual secular observance dedicated to planting and caring for trees around the worldVictory in Europe DayThe day Nazi Germany's surrender was accepted, marking the end of the war in EuropeNational day of mourningA day a government sets aside for national grief, often marked by flags at half-mastOlympic flameA flame kindled in Greece, carried by torch to light the cauldron of each Games

Good reading and sources

• Programmer's Day on WikipediaEncyclopedia
• Wikidata recordOpen data

It may contain mistakes. Traditions differ from one family, village and community to the next, and the people who keep them know them best. If something is wrong, tell us. Last refreshed 2026-10-05.