How rare your “type” is depends on what you’re measuring, but the answer is probably more interesting than you expect. Whether you’re curious about your blood type, your personality type, or something even more unusual, each system has its own rarity spectrum. Here’s where you likely fall.
Blood Type Rarity
The ABO and Rh systems together create eight common blood types, and their frequencies vary widely. Globally, O is the most common ABO group at roughly 36.5% of the population, followed by B at 26.7%, A at 23.2%, and AB as the least common at 13.6%. About 91.6% of people are Rh-positive, meaning they carry the Rh D antigen on their red blood cells. Only 8.4% are Rh-negative.
Combining ABO and Rh status is where things get more specific. If you’re AB-negative, for example, you belong to one of the smallest common blood type groups, representing roughly 1% of the population. O-positive is the most frequent combination overall.
Your Ethnicity Changes the Math
Blood type rarity isn’t the same across all populations. A large U.S. study found that 56.5% of Hispanic donors and 54.6% of North American Indian donors were type O, compared to lower rates in other groups. Rh-negative blood is far more common among white non-Hispanic donors (17.3%) than among Hispanic (7.3%), Black non-Hispanic (7.1%), or Asian donors. O-negative blood, often called the “universal donor” type, appeared in 8% of white non-Hispanic donors but only 0.7% of Asian donors. So the same blood type can be ordinary in one population and genuinely scarce in another.
This has real consequences. The American Red Cross notes that certain blood types are unique to specific ethnic or racial groups, and matching donors to recipients from the same background can be critical for patients with conditions like sickle cell disease who need repeated transfusions.
The Rarest Blood Types on Earth
Beyond the eight common types, your red blood cells carry more than 300 other antigens that can make your blood exceptionally rare. The most extreme example is Rh-null, sometimes called “golden blood,” which lacks all Rh antigens entirely. As of the most recent published count, only about 43 people across 14 families worldwide have been confirmed to carry it. These individuals can donate to almost anyone with a rare Rh blood type, but they can only receive transfusions from other Rh-null donors, making every unit of their blood extraordinarily valuable.
Another rare variant is the Bombay phenotype, where the body can’t produce the H antigen that forms the foundation for A, B, and O markers. Standard blood typing can misidentify these individuals as type O, but they can only safely receive blood from other Bombay phenotype donors. Its frequency is about 1 in 10,000 in India, 1 in 8,000 in Taiwan, and as rare as 1 in 1,000,000 in Europe.
Personality Type Rarity
If you searched this question after taking a personality test, the 16-type system (often called Myers-Briggs or MBTI) has the clearest frequency data. The types are far from equally distributed.
The most common type is ISFJ, making up about 13.8% of the general population, followed by ESFJ at 12.3% and ISTJ at 11.6%. These three types alone account for more than a third of people. At the other end, the rarest types cluster among intuitive introverts and extraverted judgers: INTJ at 2.1%, ENTJ at 1.8%, and INFJ at just 1.5%, making it the rarest of the 16 types. If you’re an INFJ, roughly 1 in 67 people shares your profile.
Here’s the full ranking from most to least common:
- ISFJ: 13.8%
- ESFJ: 12.3%
- ISTJ: 11.6%
- ISFP: 8.8%
- ESTJ: 8.7%
- ESFP: 8.5%
- ENFP: 8.1%
- ISTP: 5.4%
- INFP: 4.4%
- ESTP: 4.3%
- INTP: 3.3%
- ENTP: 3.2%
- ENFJ: 2.5%
- INTJ: 2.1%
- ENTJ: 1.8%
- INFJ: 1.5%
Enneagram Types
If you use the Enneagram system instead, most of the nine types (3, 4, 6, 7, and 9) appear in roughly balanced proportions across the population. The less common types are 1, 2, 8, and 5. Type 5 is the rarest at about 4.8% of the population, followed by Type 8 at 6.3% and Type 2 at 8.5%. A word of caution: Enneagram frequency data comes primarily from self-reported testing databases rather than controlled population studies, so these numbers are rougher estimates than blood type statistics.
What “Rare” Actually Means
It helps to put rarity in perspective. In medicine, the formal threshold for a “rare disease” is fewer than 5 in 10,000 people in the EU, or fewer than 200,000 affected individuals in the United States according to the FDA. By that standard, even the least common MBTI type (INFJ at 1.5%, or 150 per 10,000) is extremely common. AB-negative blood, at roughly 1% of the population, is uncommon but not rare in the medical sense.
True biological rarity looks more like the Bombay phenotype or Rh-null blood: conditions affecting fewer than 1 in 10,000 people, sometimes fewer than 1 in a million. Your tissue type, determined by a system called HLA, can also be genuinely rare. Some HLA allele groups appear in 0.1% or less of a given population, which is one reason finding a compatible organ or stem cell donor can take years. Country-specific donor registries have gone global specifically to improve the odds of matching patients who carry these uncommon profiles.
Neurological Rarity
Some people experience the world in ways that are statistically unusual on a neurological level. Synesthesia, where stimulation of one sense automatically triggers a sensation in another (hearing a musical note and seeing a specific color, for instance), is present in 2% to 4% of the population. That makes it uncommon but not vanishingly rare. What makes synesthesia distinctive is its variety: at least 60 different forms have been documented, covering nearly every possible pairing of senses. If you have a less common combination, like tasting words or feeling textures when you hear sounds, your specific variant could be far rarer than the 2% to 4% headline figure suggests.
Synesthesia tends to run in families, pointing to a genetic basis. Researchers believe multiple genes are involved, with different genes potentially driving different sensory pairings. So even within a single family, one person might see colors when they hear music while a relative might associate personalities with numbers.
Putting Your Rarity in Context
If your blood type is O-positive, you share it with roughly a third of the world’s population. If your personality type is INFJ, you’re in a group of about 1 in 67 people, which still means millions of people worldwide. If you carry the Bombay phenotype, you’re one of perhaps tens of thousands globally. And if you have Rh-null blood, you’re one of fewer than 50 known people on the planet.
Rarity also shifts depending on where you are. An O-negative blood type that’s relatively common in Northern Europe becomes genuinely hard to find in East Asia. An MBTI type that feels isolating in your social circle might be well represented in a different profession or culture. The number alone doesn’t capture the full picture, but it’s a useful starting point for understanding where you sit on the spectrum.