We made a freepersonality test

MBTI stands for Myers–Briggs Type Indicator. It combines four preference pairs—Extraversion / Introversion, Sensing / Intuition, Thinking / Feeling, and Judging / Perceiving—into 16 types. That is where letters such as INFP and ESTJ come from. The official MBTI has its own questionnaire and interpretation process; not every four-letter test online is the official MBTI.

These words also have specific meanings. Thinking / Feeling, for example, concerns what people give weight to when making decisions, not whether they have feelings. Introversion / Extraversion is not a measure of social skill.

16Personalities introduces 16 types with colorful characters and offers a free test. Its results look like MBTI, but it uses its own NERIS model: a four-letter format with reworked Big Five dimensions, rather than Jungian cognitive functions and their ordering.

The -A / -T at the end of a result comes from NERIS’s fifth dimension, which the official MBTI does not have. Different results on the two sites do not necessarily mean a calculation is wrong: the questions and models are different to begin with.

The Big Five usually describes Openness, Conscientiousness, Extraversion, Agreeableness and Neuroticism. Some scales reverse the last dimension and call it Emotional Stability. Results are usually scores on each dimension, not a division into five types. “Neuroticism” here is a trait name, not a mental health diagnosis.

Big Five names a family of models, not one standard questionnaire. Instruments differ in their items and length. For free options, IPIP’s public-domain items and scales include Big Five measures.

DISC often appears in team training and communication courses. In Everything DiSC, for example, the letters stand for Dominance, Influence, Steadiness and Conscientiousness. It focuses on behavior at work, such as communication pace and ways of handling disagreements. In this model, everyone has a mixture of all four styles, with different emphases.

Different providers offer different DISC products, so the name alone does not identify the questionnaire. In a team discussion, it can be a way to talk about the information and cooperation people need. It should not be used to judge ability or suitability for a job.

The Enneagram uses the numbers 1 to 9 for nine types and discusses their motives, concerns and ways of responding. Related reading also introduces concepts such as “wings.” It is more concerned with why someone acts than just what they do.

These are explanations within Enneagram theory, not personal psychological mechanisms established by a questionnaire. Even a description that feels familiar cannot establish the cause of a particular behavior.