Having a MBTI and Enneagram types on both own profiles and on famous/fictional profiles has became common in the last few years on typology community. Some MBTI/Enneagram combo are discussable impossible and I had took some time to pay attention to the combos and try to determinate which combos are impossible. Here, I tell not only the impossible combos but also the borderline requirements for most MBTI and Enneagram combos, so it is good to you to check if you have the proper borderlines for your MBTI type in the combo.
This discussion can get very much subjective, but I had decided to a more or less objective approach on this. I mainly use instead two online searches on enneagram and MBTI, and as a quite optional support, Big 5 and MBTI and Big 5 and Enneagram as well. There are many criteria and I had decided to focus on dichotomy (on letters) due to lack of proper information available for cognitive functions. And I do point which borderlines are required and which are expected.
Important: This list is not completely absolute but I think its the best reasoning on this department. The list would be at the end of the post, but I had decided to put it instead here, so the reasoning are after:
1) The impossible Enneagram and MBTI combos:
Type 1: ESTP, ESFP, ENFP, ENTP.
Type 2: INTP, ISTP, INTJ.
Type 3: INFP, ISFP, ISFJ.
Type 4: ESTP, ESTJ, ENTJ, ESFJ.
Type 5: ESTP, ENFJ, ESFP, ESFJ.
Type 6: ENTP, ENFP, ENTJ.
Type 7: INTJ, INFJ, ISTJ, ISFJ, ESFJ.
Type 8: INFP, ISFP, ISFJ, ESFJ.
Type 9: ENTJ, ESTJ.
Exceptions: Feelers with low Big 5 Agreeableness (and these usually score very high on neuroticism) can score as Type 3 and 8. Thinkers with high Big 5 Agreeableness can score as Type 2 and 9.
2) Requirements on MBTI to be fitted into each enneagram (borderline is like being on 45-55%, but being at 40-60% range is better for the context, 35-65% given a very loose definition of being borderline):
Type 1: Must be a clear J or have borderline on J/P. In a less important view, very likely be clear introverted or borderline on I/E.
Type 2: Must be a clear E or have borderline on E/I. Must be a clear F or borderline on F/T. Must be a clear J or borderline on J/P.
Type 3 and Type 8: Must be a clear E or have borderline on E/I. Must be a clear T or borderline on T/F. Must be a clear J or borderline on J/P.
Type 4: Must be a clear I or have borderline on I/E. Must be a clear N or have borderline on N/S. Must be a clear F or have borderline on F/T.
Type 5: Must be a clear I or have borderline on I/E. Must be a clear T or have borderline on T/F.
Type 6: Must be a clear I or have borderline on I/E. In a less important view, very likely to be a clear sensor or having a borderline S/N and very likely being a clear J or have borderline on J/P.
Type 7: Must be a clear or very clear Extroverted, or have a E/I borderline. Must be a clear or very clear Perceiver, or having a P/J borderline. Attention: Cant have E/I and P/J borderline at the same time.
Type 9: Must be a clear Introvert or borderline on I/E.
Exceptions: Feelers with low Big 5 Agreeableness (and these usually score very high on neuroticism) can score as Type 3 and 8 with high preference for feeling. Thinkers with high Big 5 Agreeableness can score as Type 2 with a clear preference for thinking.
3) MBTI types and their most common, usual or somewhat usual, rare (or very rare) and impossible enneagram combinations:
INFP
Most common: Type 4 (57%)
Usual: Type 5, Type 6 and Type 9.
Rare: Type 1, Type 2 and Type 7.
Impossible: Type 3 and Type 8.
INTP
Most common: Type 5 (74%).
Somewhat rare: Type 4 and Type 9.
Rare: Type 1, Type 3, Type 6, Type 7 and Type 8.
Impossible: Type 2.
INFJ
Most common: Type 4 (44%).
Usual: Type 5, Type 6 and Type 9.
Rare: Type 1, Type 2, Type 3, Type 8.
Impossible: Type 7.
INTJ
Most common: Type 5 (62%)
Usual: Type 1.
Rare: Type 3, Type 4, Type 6, Type 8 and Type 9.
Impossible: Type 2 and Type 7.
ENFP
Most common: Type 7 (39%)
Usual: Type 2, Type 4 and Type 9.
Rare: Type 3, Type 5 and Type 8.
Impossible: Type 1 and Type 6.
ENTP
Most common: Type 7 (47%)
Usual: Type 3 and Type 8.
Rare: Type 2, Type 4, Type 5 and Type 9.
Impossible: Type 1 and Type 6.
ENFJ
Most common: Type 2 (42%)
Usual: Type 3, Type 4 and Type 9.
Rare: Type 1, Type 6, Type 7 and Type 8.
Impossible: Type 5.
ENTJ
Most common: Type 8 (46%)
Usual: Type 3 and Type 1.
Rare: Type 2, Type 5 and Type 7.
Impossible: Type 4, Type 6 and Type 9.
ISFP
Most common: Type 4 (35%) and Type 9 (34%).
Usual: Type 5 and Type 6.
Rare: Type 1, Type 2 and Type 7.
Impossible: Type 3 and Type 8.
ISFJ
Most common: Type 6 (27%) and Type 2 (26%).
Usual: Type 1, Type 4 and Type 9.
Rare: Type 5.
Impossible: Type 3, Type 7 and Type 8.
ISTP
Most common: Type 5 (41%),
Usual: Type 6, Type 7 and Type 9.
Rare: Type 1, Type 3, Type 4 and Type 8.
Impossible: Type 2.
ISTJ
Most common: Type 1 (30%), Type 6 (29%) and Type 5 (29%)
Usual: Type 9.
Rare: Type 2, Type 3, Type 4 and Type 8.
Impossible: Type 7.
ESFP
Most common: Type 7 (44%).
Usual: Type 2 and Type 9.
Rare: Type 3, Type 4, Type 6 and Type 8.
Impossible: Type 1 and Type 5.
ESTP
Most common: Type 7 (39%)
Usual: Type 3, Type 6 and Type 8.
Rare: Type 2 and Type 9.
Impossible: Type 1, Type 4 and Type 5.
ESFJ
Most common: Type 2 (61%).
Usual: Type 3 and Type 6.
Rare: Type 1 and Type 9.
Impossible: Type 4, Type 5, Type 7 and Type 8.
ESTJ
Most common: Type 8 (40%).
Usual: Type 1 and Type 3.
Rare: Type 2, Type 5, Type 6 and Type 7.
Impossible: Type 4 and Type 9.
The why’s/reasoning
It is really important to me to do some observations about Enneagram 6 and 9. Enneagram 6 has some ambiguous type descriptions such as “They can be cautious and indecisive, but also reactive, defiant and rebellious”. Most tests will only focus on the cautious and security side, and not on the defiant and rebellious side. Most tests does measure this way and I will consider type 6 only on this side. Type 9 has way too much type diversity on Enneagram and basically any MBTI type can be a type 9 in Enneagram. Type 9 sometimes looks more like a zen philosophy than a type on its own.
The tables I use are here:
https://typologytriad.wordpress.com/mbti-enneagram-big-5-correlations/
Code ATER or AER: All Types Equally Represented, meaning that it is considering a population where all types have the same occurrence.
So, here are the most common MBTI types per enneagrams:
Type 1: IXXJ : In ATER, about half of enneagram type 1 are ISFJ, ISTJ and INTJ combined. World-wide, it is quite likely that about half of this enneagram type is ISFJ or ISTJ.
Type 2: EXFJ: In ATER, about 80% of this enneagram is composed by basically ENFJ and ESFJ. World-wide, it is likely that more than half of this enneagram is composed by ESFJ type.
Type 3 and Type 8: EXTJ: In ATER, a little bit less than half of this enneagram are ENTJ and ESTJ. World-wide, about half of this enneagram is composed by ESTJ and ESTP.
Type 4: INFX: In ATER, a little bit more than a half from this type are INFP and INFJ. In countries in general, about half are INFP, ISFP or ENFP.
Type 5: IXTX: In ATER, a little bit less than a half from this type are INTJ and INTP. Word-wide, most type 5 are ISTP, INTP and ISTJ.
Type 6: ISXJ: Both in ATER and world-wide, more or less (less on ATER, more on world-wide) half of this type are ISTJ and ISFJ.
Type 7: EXXP: More than 90% both in ATER and world-wide of this type are basically Extraverted Perceivers.
Type 9: Very diverse.
To determinate which combos are impossible, I simply decided to swap letters. Type 9 is way too diverse, Type 1 and 5 only got two letters so basically any type can be these types (if they have the proper borderline) while type 7 although got 2 letters, got a very clear pattern of EXXP. So, in this line, here are the impossible MBTI types per Enneagram:
Type 1: None.
Type 2: INTP and ISTP.
Type 3: INFP and ISFP.
Type 4: ESTP and ESTJ.
Type 5: None.
Type 6: ENTP and ENFP.
Type 7: INTJ, INFJ, ISTJ and ISFJ.
Type 8: INFP and ISFP.
Type 9: None.
As an alternative, I can also see which types have less than 1% of occurrence in both “surveys” to access impossible combinations, which gives:
Type 1: ESTP.
Type 2: INTJ, INTP and ISTP.
Type 3: ISFJ.
Type 4: ENTJ.
Type 5: ESTP.
Type 6: None.
Type 7: ISTJ, ISFJ and ESFJ.
Type 8: ISFJ and ESFJ.
Type 9: None.
As another alternative, I can use E/I from Big 5, Openness to Experience as Intuition, Contentiousness as Judging, and, although I do consider that quite improper, Agreeableness as Feeling, and use that to access the most common types per enneagram. And I flip the letters to arrive at which are the impossible combinations to Big 5-→MBTI view (if less than 3 letters are clear I consider none):
Type 1: None.
Type 2: INTP and INTJ.
Type 3: ISFP and INFP.
Type 4: ESFJ and ESTJ.
Type 5: None.
Type 6: ENTP and ENTJ.
Type 7: ISTJ and ISFJ.
Type 8: ISFP.
Type 9: ENTJ.
Merging this 3 lists in addictive way, I get:
Type 1: ESTP.
Type 2: INTP, ISTP, INTJ.
Type 3: INFP, ISFP, ISFJ.
Type 4: ESTP, ESTJ, ENTJ, ESFJ.
Type 5: ESTP.
Type 6: ENTP, ENFP, ENTJ.
Type 7: INTJ, INFJ, ISTJ, ISFJ, ESFJ.
Type 8: INFP, ISFP, ISFJ, ESFJ.
Type 9: ENTJ.
Just to make this list a little better, I had decided to do the opposite on Big 5 spectrum (at least 3 from 4 dimensions between Extroversion, Agreeableness, Openness and Conscientiousness). I will explain in MBTI terms as Agreeableness equal feeling (although I disagree a bit on this one), Openness as intuition (Openness is more NP but thats ok) and Conscientiousness as judging:
– Type 8 and Type 9 forms complete opposites with each other (type 8 forms ENTJ and type 9 forms ISFP).
– Type 3 and Type 9 forms opposites with each other (type 9 forms ISFP while type 3 forms EXTJ).
Thus, MBTI types which Type 3 and Type 8 are the most common are very unlikely to be Type 9, while MBTI types which Type 9 is the most common enneagram type are very unlikely to be Type 3 and Type 8. And that gives that ISFP cant be type 3 and 8 (which is already listed) and gives that ENTJ and ESTJ cant be type 9 (ENTJ is already listed, but not ESTJ). So, the list can expand as:
Type 1: ESTP, ESFP.
Type 2: INTP, ISTP, INTJ.
Type 3: INFP, ISFP, ISFJ.
Type 4: ESTP, ESTJ, ENTJ, ESFJ.
Type 5: ESTP, ENFJ, ESFP.
Type 6: ENTP, ENFP, ENTJ.
Type 7: INTJ, INFJ, ISTJ, ISFJ, ESFJ.
Type 8: INFP, ISFP, ISFJ, ESFJ.
Type 9: ENTJ, ESTJ.
But also I had decided to use the cognitive functions to give some assistance as well (had this idea just later thats why it is not in the beginning), although in this context of use it wont be super reliable. There are two ways to do this, a hard and slightly more precise one, which would be way too long to be shown, and the shortest one that is less precise, but at least more aligned with dichotomy. I decided to take the easiest one. One website made associations between enneagram and cognitive functions, although their input comes completely from dichotomy:
From this website:
– Ne and Se are associated with type 7 mostly.
– Ni is associated with type 5 (although I dont see any connection for that conceptually).
– Si is associated with type 6 and type 1.
– Te is associated with type 3 and 8.
– Ti is very strongly associated with type 5.
– Fe is very strongly associated with type 2.
– Fi is associated with type 4 and 9 (although I see few connections for that conceptually).
So, using IXXJ types as Ne-tard and Se-tard, ESXP types as Ni-tard, ENXP types as Si-tard, IXFP as Te-tard, EXFJ as Ti-tard, IXTP as Fe-tard and EXTJ as Fi-tard, and merging that with enneagram associations, we have as impossible types and enneagrams combinations:
– Type 1 (Si): ENFP and ENTP.
– Type 2 (Fe): INTP and ISTP.
– Type 3 (Te): INFP and ISFP.
– Type 4 (Fi): ESTJ and ENTJ.
– Type 5 (Ti and Ni): ESFJ, ENFJ, ESTP and ESFP.
– Type 6 (Si): ENFP and ENTP.
– Type 7 (Se and Ne): ISTJ, ISFJ, INTJ, INFJ.
– Type 8 (Te): INFP and ISFP.
– Type 9 (Fi): ENTJ and ESTJ.
Merging this list with the other one, as a final list, we have:
Type 1: ESTP, ESFP, ENFP, ENTP.
Type 2: INTP, ISTP, INTJ.
Type 3: INFP, ISFP, ISFJ.
Type 4: ESTP, ESTJ, ENTJ, ESFJ.
Type 5: ESTP, ENFJ, ESFP, ESFJ.
Type 6: ENTP, ENFP, ENTJ.
Type 7: INTJ, INFJ, ISTJ, ISFJ, ESFJ.
Type 8: INFP, ISFP, ISFJ, ESFJ.
Type 9: ENTJ, ESTJ.
Also, using the most common MBTI types per enneagram type, being complemented with Big 5, here are the requirements for each enneagram type in MBTI dichotomy:
Type 1: Must be a clear J or have borderline on J/P. In a less important view, very likely be clear introverted or borderline on I/E.
Type 2: Must be a clear E or have borderline on E/I. Must be a clear F or borderline on F/T. Must be a clear J or borderline on J/P.
Type 3 and Type 8: Must be a clear E or have borderline on E/I. Must be a clear T or borderline on T/F. Must be a clear J or borderline on J/P.
Type 4: Must be a clear I or have borderline on I/E. Must be a clear N or have borderline on N/S. Must be a clear F or have borderline on F/T.
Type 5: Must be a clear I or have borderline on I/E. Must be a clear T or have borderline on T/F.
Type 6: Must be a clear I or have borderline on I/E. In a less important view, very likely to be a clear sensor or having a borderline S/N and very likely being a clear J or have borderline on J/P.
Type 7: Must be a clear or very clear Extroverted. Must be a clear or very clear Perceiver.
Type 9: Must be a clear Introvert or borderline on I/E.
Typology Triad 
Well I fall into the impossible category. I am an ESTJ enneagram 4 and indeed it has taken me a long time to understand myself as there are so many contradictions. Very interesting post.
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So I am an INFJ. Type 7. Am an impossible person. yay
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As a INFP, I match your analysis nearly completely. I’m a type 4w5 with serious 9 tendencies. My bottom two were 3 & 8.
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