The one-paragraph version
16Personalities is built on top of the MBTI. You answer the same four-letter questions (E/I, S/N, T/F, J/P), so most people get the same four letters on both. The difference is that 16Personalities adds a fifth dimension, called Identity, which splits every type into an Assertive (-A) and a Turbulent (-T) version. Same DNA, an extra personality trait.
Where 16Personalities came from
16Personalities is run by NERIS Analytics Limited and is the most-visited personality site on the internet. It is not the official MBTI® — that's a paid, proprietary instrument run by The Myers-Briggs Company. 16P is a self-published model built from publicly known MBTI theory plus its own original fifth dimension.
Because 16Personalities is free, polished and easy to share, it has become the de facto way millions of people 'do the MBTI' — even though, strictly speaking, they are two different products.
The MBTI baseline: four dimensions
Both tests start from the same four-letter framework:
| Pair | Letter A | Letter B | What it measures |
|---|---|---|---|
| Energy | E — Extraversion | I — Introversion | Where you recharge |
| Information | S — Sensing | N — Intuition | How you take in the world |
| Decisions | T — Thinking | F — Feeling | How you choose |
| Structure | J — Judging | P — Perceiving | How you approach life |
The 16Personalities twist: a fifth trait
The axis is independent of the four letters. Any of the 16 MBTI types can come in either flavor — INFP-A and INFP-T, ESTJ-A and ESTJ-T — giving 16Personalities a working set of 32 types instead of 16. That's where the '16P' name comes from: 16 × 2 = 32.
- Assertive (-A) — self-assured, even-tempered, resilient under stress. Less likely to second-guess.
- Turbulent (-T) — self-aware, success-driven, prone to self-doubt. More likely to chase growth.
Key differences side by side
| Aspect | MBTI | 16Personalities |
|---|---|---|
| Cost | Paid (official MBTI®), or unofficial free versions | Free |
| Number of types | 16 | 32 (16 letters × A/T) |
| Official status | Proprietary, run by The Myers-Briggs Company | Independent, run by NERIS Analytics |
| Extra dimensions | None beyond the four letters | Identity: Assertive / Turbulent |
| Format | Mostly long-form questionnaire, sometimes proctored | Online, self-paced, no proctoring |
| Result depth | Often a paid detailed report | Free long-form type profile on the site |
| Best known for | Workplace and corporate use | Internet culture, memes and self-discovery |
Why the four letters usually agree
Because both tests ask the same questions in spirit, most people land on the same four-letter type whichever they take. If 16P says you're an INTJ, an MBTI-style test almost certainly will too. What changes is the suffix: 16P will then tell you whether you are INTJ-A or INTJ-T — a nuance the MBTI itself does not give you.
Where they can disagree is at the boundaries. If you sit close to the middle on Thinking/Feeling or Judging/Perceiving, even small wording differences can tip your letter. The fifth A/T axis is independent, so an MBTI 'ENFJ' could be ENFJ-A on one test and ENFJ-T on another — without either being wrong.
Which one should you take
- Curious and casual? Start with 16Personalities — it's free, fast and the report is rich enough for self-reflection.
- Need an 'MBTI' for a workplace or team workshop? Take the MBTI-style version, since that's the vocabulary most corporate training uses.
- Want the full picture? Take both, days apart. If your four letters match and only the A/T differs, you have a very clean signal.
A fair verdict
Try both, free, side by side
Take the 16Personalities test and the MBTI test back-to-back and see whether your four letters match — and whether the A or T adds anything new.
Take the 16Personalities testFrequently asked questions
Are 16Personalities and MBTI the same test?
Not exactly. They share the same four-letter base, but 16Personalities adds an Assertive/Turbulent fifth trait and is run independently of the official MBTI®.
Is 16Personalities free?
Yes. The full test, the result profile and most of the supporting material on the 16Personalities site are free to use. The official MBTI® is paid and usually proctored.
Does 16Personalities give you an MBTI certificate?
No. Only The Myers-Briggs Company and its licensed practitioners issue official MBTI® certifications. A 16Personalities result is a 16P result, even though the four letters look the same.
Which test is more accurate?
Neither, really — they answer different questions. For research validity the Big Five leads; for everyday reflection and a memorable type label, MBTI-style tests (16P included) are the most popular choice.
Can my type change between the two tests?
The four letters usually agree. The suffix (-A vs -T) is independent and can move with life circumstances — many people flip on it across stressful years.
PersonaQuiz quizzes and articles are for entertainment and self-reflection only. They are not psychological evaluations and must not be used for clinical, medical, or hiring decisions.
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Sources & further reading
- 16Personalities — Our Theory — The official explanation of the Assertive/Turbulent fifth dimension this article covers.
- 16Personalities — All 32 Type Profiles — The full grid of 16 × 2 type profiles, including all -A and -T variants.
- Verywell Mind — Myers-Briggs Type Indicator — Independent, research-aware overview of the official MBTI framework.