๐ How Rare Are You in Indonesia?
๐ฎ๐ฉ Genetic Landscape of Indonesia
Indonesia is the world's largest archipelago โ 17,000+ islands spanning 5,000km, home to over 300 ethnic groups. This island isolation created remarkable genetic pockets. Papuans in eastern Indonesia carry Denisovan DNA (up to 5%), one of the highest concentrations on Earth. The Bajau 'sea nomad' people evolved larger spleens for deep-sea diving. Javanese, Sundanese, Balinese, and Minangkabau all show distinct genetic profiles despite geographic proximity.
Descent rules change as you move between islands. Batak families from northern Sumatra carry a marga, a clan name that fixes ancestry and rules out marriage inside it, while the Minangkabau of West Sumatra pass property and clan membership down the mother's line and are widely described as the largest matrilineal society in the world. Names follow the same local logic. Many Javanese use a single name with no family name behind it โ Sukarno and Suharto were the norm rather than exceptions โ and Balinese children are commonly named by birth order, so Wayan, Made, Nyoman and Ketut cycle round and then begin again with a fifth child. Decades of state-organised transmigration from crowded Java to the outer islands then stirred these patterns together.
๐ข Your Birthday Is Sitting Inside Your ID Number
Indonesia gives every resident a sixteen-digit number, the Nomor Induk Kependudukan, or NIK. Law 23 of 2006 says it is given once your biodata has been recorded, and that it is valid for life. Government Regulation 40 of 2019 sets out what those digits are, in wording carried over from the 2007 regulation it replaced. The first six are codes for the province, the regency or city, and the district where you were living when you registered. The last four are a serial the registration system issues automatically. The middle six are the day, month and year you were born.
The middle six carry one more thing. The regulation says that for women the day of birth has 40 added, so a woman born on the 7th appears as 47 and a man as 07. Inside the number sex is not a separate digit โ it is arithmetic done to the date. It also means two people whose NIKs share their first twelve digits share a registration district and a birth date, which is far narrower than sharing a birthday alone โ see how rare yours is on our birthday page.
๐๏ธ Eye Color
| Dark Brown | 95% |
| Brown | 4% |
| Other | 1% |
๐ Hair Color
| Black | 96% |
| Dark Brown | 3% |
| Other | 1% |
๐ฉธ Blood Type
| O+ | 37% |
| B+ | 25% |
| A+ | 24% |
| AB+ | 7% |
| O- | 3% |
| A- | 2% |
| B- | 1.5% |
| AB- | 0.5% |
Trait frequencies on this page come from public and institutional datasets โ see Data Sources.
🧮 Calculate Your Rarity in Indonesia
Pick your eye colour, hair colour and blood type. The calculator uses Indonesia's own figures from the tables above, not world averages.
This is an estimate, not a measurement. It multiplies three national frequencies as if they were independent, and they are not: eye and hair colour share pigmentation genes, so a combination that tends to run together, such as blue eyes with blonde hair, is more common than the multiplication suggests, while one that rarely does, such as blue eyes with black hair, is rarer. Blood type is independent of both. The frequencies are national averages from public datasets — see Data Sources.
That number describes the body you were born with. Fraeon, our other site, does the same arithmetic for the part you chose: the films, series, games, books, anime and manga you have actually finished. Start your log →
โ๏ธ The 1972 Spelling Reform, and the Signature On It
On 16 August 1972 President Soeharto signed Keputusan Presiden No. 57, declaring the next day, 17 August, the official start of the Ejaan Bahasa Indonesia yang Disempurnakan, the reformed spelling. Six digraphs went: tj became c, dj became j, j became y, nj became ny, sj became sy, ch became kh. Words changed on paper: djual to jual, ajam to ayam, njonja to nyonya. The decree gave government deadlines: official correspondence from 1 January 1973, forms from 1 April 1973.
Those deadlines covered letters and forms. The decree says nothing about the names already written on people's documents, and many Indonesian personal names do not follow the spelling rules. The decree is its own illustration: it declares the new spelling in force while being written in the old one โ Djakarta, berlakunja โ and it is signed SOEHARTO, keeping an oe that a different reform, back in 1947, had already replaced with u (goeroe became guru). A name count in Indonesia is counting spellings as much as names: one name can sit in the records under more than one of them.
๐๏ธ A Birthday That Comes Round Every 35 Days
Java runs two weeks at once. Alongside the seven-day week there is the pasaran, a five-day week: Legi, Pahing, Pon, Wage, Kliwon. Your weton is the pair โ the weekday you were born on plus the pasaran day โ and it repeats every 35 days (7 ร 5), not every year. A 2020 paper by Karjanto and Beauducel on the Javanese calendar's arithmetic lists its cycles: the five-day pasaran, the 35-day wetonan, the 210-day pawukon, the eight-year windu and the 120-year kurup.
The calendar has been in use for close to four centuries and stacks three systems together: Hindu Saka reckoning, Islamic lunar months and the Gregorian year. The join is datable. In 1633 Sultan Agung of Mataram adopted the lunar months but did not restart the year count at the Hegira, carrying the Saka number forward from 1555 instead. So one Javanese birth date can be written three ways at once.
โญ Rare Facts About Indonesia
Where the numbers on this page come from
The population figure is from Badan Pusat Statistik (Statistics Indonesia), the agency that runs the census and reports to the president. The other three are not Indonesian official statistics. No Indonesian census, ID document or national survey we could find records eye or hair colour, so those two figures are modelled estimates rather than counts. Height and blood-group shares come from published research and donor studies, not a government register. More on our Data Sources page. Last checked September 2026.