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A free 16Personalities alternative: same four letters, measured as Big Five traits with percentiles

By the 64 Types team · Updated October 31, 2026 · 5 min read · 8 peer-reviewed sources

If you like the four-letter format of 16Personalities but want to see how it is measured, [64 Types](/test/) is a free alternative: 62 public-domain questions, about 8 minutes, no sign-up, in 40 languages. It keeps the familiar codes such as INFJ, scores each letter as a Big Five trait with a percentile, flags letters that sit near the midpoint, and adds two traits the four letters leave out: emotional stability and honesty-humility.

Below we compare the two approaches using 16Personalities’ own descriptions of its model, explain what the extra letters add, and say when either test is the better fit. 64 Types is not affiliated with 16Personalities, NERIS Analytics or the Myers-Briggs Company.

What 16Personalities measures

16Personalities builds its result from five aspects: Energy (Introverted or Extraverted), Mind (Intuitive or Observant), Nature (Thinking or Feeling), Tactics (Judging or Prospecting) and Identity (Assertive or Turbulent). The first four give the four letters; Identity adds the -A or -T suffix.[1] The company says it reworked the dimensions of the Big Five rather than using Jungian concepts.[1]

Its model is called the NERIS Type Explorer and is proprietary: the questions and scoring are not published, and the company asks that its codes not be treated as interchangeable with the MBTI.[2] That is a reasonable business choice, but it means outsiders cannot check how a given answer turns into a letter.

How 64 Types differs

Side by side (16Personalities as described on its own pages; 64 Types as built on this site)
16Personalities64 Types
QuestionsProprietary[2]Public-domain IPIP items anyone can inspect[3]
Four lettersEnergy, Mind, Nature, Tactics[1]Extraversion, Openness, Agreeableness and Conscientiousness, the Big Five traits the four MBTI scales line up with[4]
Scores shownPercentage leaning to each side[1]Percentiles against open research data[5]; letters near the midpoint are flagged with the alternative type
Stress and moodIdentity: Assertive or Turbulent[6]Emotional stability (C = Composed, R = Responsive), the Big Five trait the four letters miss[4]
Honesty and modestyNot measuredHEXACO Honesty-Humility (M = Modest, A = Ambitious)[7][8]
CostFree testFree test; optional one-time 29-facet Deep Report[9]

The midpoint flag matters because trait scores pile up near the middle rather than splitting people into two camps,[10] which is the main reason type letters change when people retake a test.[11] Seeing “you are close to the line on J/P” is more honest than a hard letter.

Your four letters, read as Big Five traits

Researchers who correlated the MBTI scales with a Big Five inventory found that each of the four letter pairs lines up with one Big Five trait: Extraversion–Introversion with Extraversion, Sensing–Intuition with Openness to Experience, Thinking–Feeling with Agreeableness and Judging–Perceiving with Conscientiousness.[4] 64 Types uses exactly this mapping, so your letters keep their usual meaning while each one comes with a score.

How each letter pair maps to a Big Five trait (McCrae & Costa, 1989)[4]
LettersBig Five traitHigh score means
E / IExtraversionE: energised by people and activity
N / SOpenness to ExperienceN: drawn to ideas, imagination and novelty
F / TAgreeablenessF: warm, cooperative, trusting
J / PConscientiousnessJ: organised, planful, persistent

A percentile tells you where you stand compared with other people: a 70th percentile on Extraversion means you scored higher than about 70% of the comparison group. Two people with the same letter can sit at the 52nd and the 95th percentile, which a letter alone hides. 64 Types compares your scores with large open datasets of public-domain IPIP answers collected online.[5]

Because the questions are the public-domain IPIP Big Five markers,[3] anyone can read exactly which statements feed each score. If you disagree with a result, you can see which answers moved it.

What the two extra letters add

Emotional stability. When McCrae and Costa compared the MBTI with a Big Five inventory, its four scales matched four of the five traits but none captured neuroticism.[4] 16Personalities’ Assertive/Turbulent scale covers similar ground;[6] 64 Types measures it with standard public-domain items and reports it as the fifth letter. More in Assertive vs Turbulent explained.

Honesty-Humility. The HEXACO model found a sixth broad trait (sincerity, fairness, modesty and lack of greed) in personality-descriptive words across many languages.[7] It is measured by the HEXACO Personality Inventory[8] and is the sixth letter in a 64 Types code. More in Honesty-Humility explained.

Why your type can change between tests

Many people get INFJ on one test and INFP or ENFJ on another, or on the same test a few weeks later. Studies of the MBTI found that a large share of people get a different four-letter type when retested after a few weeks.[11] The usual reason is not that the person changed but that scores on each scale bunch up around the middle instead of forming two separate groups.[10] Someone just above the line on Judging today can land just below it tomorrow.

There are two honest ways to handle this. One is to show how strongly someone leans, which 16Personalities does with its percentages.[1] The other is to compare each score with other people and say plainly when a letter is a near-tie. 64 Types does the second: a letter within a few percentile points of the middle is marked as borderline, and the result shows the type you would get if it tipped the other way.

Real change also happens, slowly. On average people become more emotionally stable, agreeable and conscientious across adulthood.[12] More in Can your personality type change?

Which test should you take?

  • You want the most widely shared type descriptions: 16Personalities. Its profiles are what most friends and social posts refer to.
  • You want to see your trait scores, percentiles and borderline letters, from questions you can inspect: 64 Types.
  • You want stress reactivity or honesty-humility in your result: 64 Types adds both as letters.
  • You want the test in your own language: 64 Types runs in 40 languages, including Hindi, Bengali, Indonesian, Swahili, Tamil, Hausa and Amharic, with the same questions and norms in each.
  • You want facet-level detail (29 facets): the optional Deep Report uses the public-domain IPIP-NEO-120.[9]
Tip

Taking both is fine: your four letters usually agree when you are clearly on one side of a scale. Where they disagree, check whether 64 Types flags that letter as borderline.

Neither test is a clinical or hiring tool. For how accurate personality tests are in general, see Are personality tests accurate?

Frequently asked questions

Is there a free alternative to 16Personalities?

Yes. 64 Types is free, takes about 8 minutes (62 questions), needs no sign-up and is available in 40 languages. It uses the same four-letter codes, scored as Big Five traits with percentiles, plus emotional stability and honesty-humility.

Is 64 Types the same as 16Personalities?

No. They are separate and unaffiliated. 16Personalities uses its proprietary NERIS Type Explorer; 64 Types uses public-domain IPIP items and open norms, and adds a sixth trait from the HEXACO model.

Will I get the same four letters on both tests?

Usually, when you are clearly on one side of each scale. Letters near the midpoint can flip between tests or retakes; 64 Types marks those letters and shows the alternative type.

References

  1. 16Personalities (NERIS Analytics Limited). Our theory. Retrieved 21 October 2026, from https://www.16personalities.com/articles/our-theory
  2. 16Personalities (NERIS Analytics Limited). 16Personalities AI reference. Retrieved 21 October 2026, from https://www.16personalities.com/for-ai
  3. Goldberg, L. R. (1992). The development of markers for the Big-Five factor structure. Psychological Assessment, 4(1), 26–42.
  4. McCrae, R. R., & Costa, P. T. (1989). Reinterpreting the Myers-Briggs Type Indicator from the perspective of the five-factor model of personality. Journal of Personality, 57(1), 17–40.
  5. Open Psychometrics (n.d.). Raw data from online personality tests: Big Five Personality Test, IPIP 50 items (BIG5.zip, 19,719 records, collected c. 2012). Retrieved 22 October 2026, from https://openpsychometrics.org/_rawdata/ (frequencies computed by 64 Types with scripts/type_frequency.py)
  6. 16Personalities (NERIS Analytics Limited). Assertive vs. Turbulent personality traits [Identity: Assertive (-A) vs. Turbulent (-T)]. Retrieved 21 October 2026, from https://www.16personalities.com/articles/identity-assertive-vs-turbulent
  7. Ashton, M. C., Lee, K., Perugini, M., Szarota, P., de Vries, R. E., Di Blas, L., Boies, K., & De Raad, B. (2004). A six-factor structure of personality-descriptive adjectives: Solutions from psycholexical studies in seven languages. Journal of Personality and Social Psychology, 86(2), 356–366.
  8. Lee, K., & Ashton, M. C. (2004). Psychometric properties of the HEXACO Personality Inventory. Multivariate Behavioral Research, 39(2), 329–358.
  9. Johnson, J. A. (2014). Measuring thirty facets of the Five Factor Model with a 120-item public domain inventory: Development of the IPIP-NEO-120. Journal of Research in Personality, 51, 78–89.
  10. Bess, T. L., & Harvey, R. J. (2002). Bimodal score distributions and the Myers-Briggs Type Indicator: Fact or artifact? Journal of Personality Assessment, 78(1), 176–186.
  11. Pittenger, D. J. (2005). Cautionary comments regarding the Myers-Briggs Type Indicator. Consulting Psychology Journal: Practice and Research, 57(3), 210–221.
  12. Roberts, B. W., Walton, K. E., & Viechtbauer, W. (2006). Patterns of mean-level change in personality traits across the life course: A meta-analysis of longitudinal studies. Psychological Bulletin, 132(1), 1–25.

How we write guides: every research claim cites a peer-reviewed source, effect sizes are reported as published, and advice that goes beyond the evidence is labelled as a practical tip. See our methodology. Found an error? Email [email protected].

Related guides

What -A and -T mean in personality types: Assertive vs Turbulent, and how it relates to neuroticism

What the -A and -T in codes like INFP-T mean, how 16Personalities defines Assertive and Turbulent, and how the idea compares with the Big Five trait neuroticism.

MBTI vs Big Five: how the 16 types map onto the scientific model

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