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 discussably impossible and might come from errors at self-report and typing others and I had took some time to pay attention to the combos and try to determinate which combos are impossible. This discussion can get 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 (on this page: https://typologytriad.wordpress.com/mbti-enneagram-big-5-correlations/)
This is an updated version of this article:
With the changes coming from Jung Typology Explained (https://typologytriad.wordpress.com/2021/01/12/sojt/), I had decided that conceptually it is more appropriate to separate MBTI and Jung Typology for the combinations with the Enneagram. Using them separated is more systematic and Jung Typology is easier than the cognitive functions “internet” theory and their stack (Grant Stack and Cognitive Functions), so I can even explain conceptually the restrictions pointed out by data. The problem is that the data is under some heavily, but not totally, influence of the cognitive functions paradigm.
E/I
The first big common divide for MBTI, Jung Typology and Big 5 as well is Extraversion and Introversion, and I had mentioned Big 5 because the Big 5 can be used to expand the concept of E/I. So the first thing to do is to evaluate each enneagram in terms of E/I. But I am adding a middle to that divide, so the division here is: Extraversion, Ambiversion and Introversion. I know almost nobody uses ambiversion on their types, however this term is interesting because some combos (like Extraverted e5) implies in ambiversion. Notice that this is looking at the person and profiles on long term: People on short term due to some reasons can get particularly Extraverted or Introverted, like they are having an Introverted or Extraverted “phase” (Jung does even mention that). Same happens to other aspects as well. And there is nothing that really points straight that type does not change with time (specially the enneagram, this one is sort of prone to change), so if a person sticks to a type on MBTI while actually changing and years later go to the enneagram changed or vice versa, there is an actually small chance of an impossible combo.
Enneagram Type 1: In statistics, Enneagram 1 is ambivert on Big 5, and slightly more populated by Introverts on MBTI. So, this type is basically indifferent to E/I, and people from this type can be Introverted, Ambiverted or Extraverted.
Enneagram Type 2: On Big 5, e2 is predominately Extraverted, while on MBTI the majority of types are Extraverts. This type has Extravert characteristics that includes an orientation towards people and their basic desire and fear is socially oriented (oriented towards other people). For these reasons, no 2 can be properly ever a strong Introvert, and 2s can be Extraverts or Ambiverts. So, for example, when a profile combo like INFP 2 shows up, that actually means that the person is an ambivert.
Enneagram Type 3: On Big 5, e3 is predominantly Extraverted, while on MBTI the majority of types are Extraverts. This enneagram type has Extravert characteristics that includes an orientation towards the external image that they pass to the public, wanting to have the attention and to impress others. Because of this, no 3 can be properly ever a pronounced Introvert, so 3s can be Extraverts or Ambiverts. So, for example, when a profile combo like INTJ 3 shows up, that actually means that the person is an ambivert.
Enneagram Type 4: On Big 5, e4 is predominantly Introvert, while on MBTI the majority of types are Introverts as well. This enneagram type has Introvert characteristics being self-absorbed, highly introspective and reserved. The expression of this type is mostly on some artistic forms or secondary forms rather than an external orientation or a social kind of expression. Due to this, no 4 can be properly ever a pronounced Extravert, and 4s can be Ambivert or Introverts.
Enneagram Type 5: On big 5, e5 is predominantly Introvert, while on MBTI more than 90% are Extraverts. This enneagram type has Introvert characteristics: Secretive, isolated and intense. No 5 can properly ever be a pronounced Extravert, but only Introvert or Ambivert.
Enneagram Type 6: On Big 5 and on MBTI it is predominantly Introvert, but the data is very biased towards phobic 6 rather than counter-phobic 6, and the phobic means very cautious, which hits a Jung E/I factor. However, in neutral terms, e6 is very close to the undifferentiated type, meaning that it can be Introvert, Ambivert and Extravert, even though Introvert seems to be the most common.
Enneagram Type 7: On Big 5, e7 is predominantly Extravert, while on MBTI the majority of 7s are Extraverts. This type has Extravert characteristics: Excitement-seeking (its an Extravert facet of Big 5 Extraversion), busy (and that means high activity, and activity is a facet of Big 5 Extraversion) and this profile even has extroversion as a characteristic in some of the descriptions. So, this type cannot be a properly introvert, being only an Extravert or Ambivert.
Enneagram Type 8: On Big 5, e8 is predominantly Extravert, while on MBTI most of 8s are Es. Conceptually, this type is tricky and can be divided in two. Some 8s, which are minority (probably really minority), very value their own autonomy and is highly protective of it without feeling that they must control their environment, and these may lack assertiveness. These kind of 8s can be either I, A or E. Other 8s, which are the majority, also value their own autonomy however they do have a feeling that they must control their environment plus are confrontational and assertive. These cannot be properly an Introvert because wanting to control the environment is an objective quite tied to Extraversion that evokes assertiveness, and they can only be Ambiverts or Extraverts.
Enneagram Type 9: On Big 5, e9 is moderately Introverted, while on MBTI most of 9s are Is. However, in conceptual terms, enneagram 9 doesn’t have much strong ties to any E or I characteristics, sometimes even possessing both (the fear of loss or separation might be environment related; While desire of internal peace is an internal pursue), so 9s can be Extraverts, Ambiverts or Introverts, however most 9s will be towards Introversion, and one of the reason I theorize for this is that on the common environment some degree of isolation and self-protection is required in order to have peace.
PS: For the MBTI combos and Jung typology, it is totally okay to assign a slightly E or slightly I to ambiverts, but we must notice that is not a high and pronounced preference.
MBTI
It is good to remember that type 6, without phobic or counterphobic bias, is the ambivalent type of the enneagram. “Whatever we say about 6s, the opposite is often true”. Due to that, profiles that have a lot of borderlines on MBTI, or basically profiles that are in the middle on MBTI on 3-4 dichotomies, does fulfill the criteria of ambivalence and are 6s rather than a different combo. Due to that, I can draw some few restrictions of MBTI types and Enneagram combos, but way less than my earlier version (but there are some restrictions on Jung Typology as well, and they are stronger).
Enneagram 1: Almost a 100% of 1s are Js, and 1 profile has J characteristics of being perfectionist, organized and try to “maintain high standards”. A little bit less than 90% of 1s are xSxx and/or xxTx types on MBTI, and 1 has characteristics related to T (rational and the morality is dogmatic like a Jung Te type), but there are not much signs of sensing conceptually. So, a 1 profile has a tendency to be XSTJ, which means that ENFP 1 and INFP 1 would be too ambivalent. It is also good to notice that in statistics the number of ESTPs 1s is absolute zero, so the impossible MBTI for type 1s are ENFP and ESTP, and by bridging ESTP and ENFP, I include ESFP as well.
Enneagram 2: Almost 100% of 2s are Feelers, and this has to do with this profile having lots of Feeling traits, specially on Extraverted attitude: Caring, people-pleasing, sentimental, interpersonal, etc… Most of 2s are Js, even though conceptually the links are weaks, and that is partially due to the possessiveness characteristic of 2s. Most E2 are sensors, but that is due to most people around the world being sensors (about 70% of world and E2 are sensors). So, a 2 profile has a tendency to be EXFJ, which means that ISTP and INTP 2s would be too ambivalent. It is also good to notice that statistically the number of INTJs and ISTJs 2 are very close to zero (like 1 per thousand on INTJ or less; and that is similar for ISTJ) with lot of ambivalence. So, INTP, ISTP, ISTJ and INTJ are impossible combos for enneagram 2 (actually, ISTJ/INTJ 2 are just extremely unlikely).
Enneagram 3: 3s are predominantly Thinkers and Judgers, because the 3 profile is very TJ friendly, having objectives, goals, ambitions, etc… Sensors are majority but that is proportional to the world-wide statistic. So, 3s have tendency to be EXTJs, so ISFP and INFP would be too ambivalent. It is also good to notice that on the stats the number of ISFJs 3 are near zero, so, INFP, ISFP and ISFJ are impossible combos for enneagram 3.
Enneagram 4: More than 90% of 4s are Feelers. That is, because, you know, 4 is “the romantic” type, is sensitive and is full of other Feeling traits. Fours are also more intuitives, due to being more introspective and artistically creative. Fours are also in majority Perceivers, even though in conceptually terms there is not much connection. So, a 4 profile has a tendency to go INFX, meaning that ESTJ and ESTP are too ambivalent to be 4s. It is also good to notice that, statistically, the number of ENTJs 4 are near zero, so, ESTJ, ESTP and ENTJ are impossible combo for e4.
Enneagram 5: About 90% of 5s are Thinkers. This is because this is the cerebral or “mastermind” type of the enneagram. E5 is also populated with more Perceivers than average, partially due to curiosity and higher perception, even though this factor is weak. Also, E5 is more populated with intuitives, and this relates to them dealing with a lot of ideas, theory, thoughts and imaginary constructs. Due to this, enneagram 5 is more towards INTP (and more than 2/3 of INTPs are enneagram 5), so ESFJ is incompatible with e5. Also notice that ESTP is statistically on zero absolute in number of e5s. ESFP is the Extraverted type that is the MBTI type that is simultaneously cousin of ESFJ and ESTP and also extremely unlikely to be a 5 in general terms. So, ESFJ, ESFP and ESTP are impossible combos for ennea 5.
Enneagram 6: As explained, 6s in general can be of any MBTI type (there are only restrictions to phobic 6 or counter-phobic 6 but I won’t bother about them this time).
Enneagram 7: The number of Js on E7 is close to zero, and this relates to this type being spontaneous and versatile along with other Perceiving traits. Sevens does not have particular inclinations on N/S or T/F, meaning they are, in general, EXXP types. But notice that the number of ISTJs and ISFJs that are 7 are in zero absolute, so ISTJ and ISFJ are incompatible with type 7 (and INFJ/INTJ is problematic and just extremely unlikely).
Enneagram 8: Almost all of 8s are thinkers, and this is because tough vs tender is on the T/F facet, but also due to 8 being more “conflict-seeking” (more confrontational), and they are slightly more S (partially due to being more materialistic) and slightly more J (in part because ofassertiveness), so 8 points to the ESTJ type, meaning that INFP is a bad combo. Also notice that the number of ISFJs and ESFJs are zero absolute, however ESTJ and ESFJ are cousin to each other. So, the restrictions would be INFP and ISFJ, and the introvert between them is ISFP, so the impossible combos for this ennea type are INFP, ISFP and ISFJ.
Enneagram 9: 9 is slightly ISFP, and conceptually the P relates to “easy-goingness” and Feeling connects with the avoidance of conflicts. N/S does not link much. However, all these links are too low and weak, and also 9 has a weak sense of self that has room for ambivalence, so any MBTI type can be an Enneagram 9, although the most accurate saying is that any 9 can be any MBTI type (and per 9 description… “9s can have the intellect of INTPs, the lovely side of ESFJs, etc…”).
Jung Typology
I will explain this in terms of functions and in terms of 39 types, and, of course, the function related stuff (F,T,S,N); what I already explained on the MBTI part I won’t explain twice!
Enneagram 1: This one is a little bit complicated and controversial. At the beginning, a 1 is more T and then S, and ambivert, so the 1 mostly matches the T-s type, but not totally, however it is as if J and Conscientiousness are the primary function rather than T or S, so combining with a i orientation, I would say that Ti-s and Si-t are the most likely 1s, even though Ti-s is likely to be a 5 as well, while a Ne-f and a Fe-n would be the least likely to be ones. Ne kind of opposes the dogmatism from the 1 profile, so I would say that Ne-f 1 is an impossible combination (actually, my argument is long but any Ne and Ne-t are impossible combos as well), but the same can’t really be said to Fe-n.
Enneagram 2: This one is super easy. The dominant function is F, the orientation is E. So, Fe-s, Fe-n and Fe are the most likely, while Ti-n, Ti-s and Ti can’t be 2s, that would be inconsistent. And another thing to say is that the function F is very pronounced here, so any T type would be actually a matter of inconsistency, because 2s can’t have F as inferior function. So, T, Ti, Te, regardless of the auxiliary function, are inconsistent as well. “What about ESTJ 2?” Since neither T or F would be pronounced, they would be less differentiated, so ESTJ 2 must be a S-dom.
Enneagram 3: This one is easy as well. The dominant function is T, the orientation is E. So, Te, Te-s and Te-n are the most likely, while Fi, Fi-n and Fi-s are the inconsistent ones and the impossible combos would be Fi 3, Fi-n 3, Fi-s 3.
Enneagram 4: This one has both an N and an F trend. With I, that would be Fi-n and Ni-f as the most trend types, so Te-s and Se-t would be the inconsistent ones. The F function is also very very strong here, so any T type regardless of auxiliary function or E/I orientation would be a matter of inconsistency as well. “What about INTP 4?” That would be a Ni-dom, because neither T or F are pronounced, making these functions less differentiated, so a INTP 4 must be a N-dom.
Enneagram 5: This one is super easy, it contrasts with 2 entirely. The dominant function is T, with a I orientation, while N is a trend, so the poster type is a Ti-n, while the complete opposite is a Fe-s, that would be inconsistent with enneagram 5. T is super strong here, so this type cannot have inferior T, which makes every F type regardless of orientation or auxiliary function inconsistent. “What about INFP 5?” That must be a Ni-dom for the same reasons INTP 4 is a Ni-dom as well (and INTP 4 & INFP 5 are actually identical in Jung typology even though they are quite different profiles).
Enneagram 6: Its the undifferentiated type, and the key is… Undifferentiation! A 6 cannot be a fully differentiated type (not any of the 16 types that are fully differentiated), even though some of them might score Si-t and Si-f on essays, but that… Would be more the essay failing to capture reactivity. A 6 is more likely to be a Si type, and my theory for that I will cover on another article because it is quite big.
Enneagram 7: E7 is undifferentiated on the functions, but any 7 can be differentiated, so there are no restrictions on Jung typology on this type except on that 7s can’t be pronounced introverts. But the majority of 7s, perhaps something like 90%, should be Extraverted Irrational types (Ne and Se types, with or without auxiliary functions).
Enneagram 8: E8 is a complicated one. Because yeah, most of them are T, yet enneagram 8 does not fit at all the description of a Rational type, even if they match some aspects of the Te profile, where Te, Te-s and Te-n are the most likely 8s. This is the enneagram (with 9) that makes me think that there might be functions missing on the Jung system, and an irrational one to be a clear preference for Type 8 (I am almost sure of that). So I can’t really say that 8s can’t have inferior T, but most of them will score as primary T, as Te, Te-n, or Te-s to be more specific, so at least I can say that Fi, Fi-n and Fi-s are inconsistent with enneagram 8 (although I am not really sure of that, exactly because of this feeling that there are functions missing here).
Enneagram 9: 9 is skewed towards F and S with i orientation (so the poster 9 is Fi-s; But there is the same problem of E8 that an irrational function might be missing), but it is not pronounced on neither, and it should be less differentiated than average, so I can say at least that N and T types with an Extravert orientation can’t be 9s because they are the reverse of average 9 and fully differentiated, so Ne-t and Te-n can’t be 9s. “What about ENTP or ENTJ 9?” Both pure Ne-dom, N-t or T-n! Actually, can be Te-dom if the “intellectual” formula is very 9 friendly (but imagining something like a Te-dom with a zen philosophy from Buddhism (on a slightly modified version to be even more 9 friendly) highly engaged on spirituality is sort of bizarre.. And that would probably not score as Te type in most of the tests).
So, here is the entire list of impossible combos and the predicted borderlines.
Impossible MBTI/Enneagram & Jung Type/Enneagram combos
Type 1: ENFP, ESFP, ESTP, INFP; Ne, Ne-f, Ne-t.
Type 2: INTP, ISTP, INTJ, ISTJ; T, Ti, Te, Ti-n, Ti-s, Te-n, Te-s.
Type 3: INFP, ISFP, ISFJ; Fi, Fi-n, Fi-s.
Type 4: ESTJ, ESTP, ENTJ; Se-t, T, Ti, Te, Ti-n, Ti-s, Te-n, Te-s.
Type 5: ESFJ, ESFP, ESTP; F, Fi, Fe, Fi-n, Fi-s, Fe-n, Fe-s.
Type 6: N/A (all MBTIs can be 6s); All 16 highly differentiated types.
Type 7: ISTJ, ISFJ; N/A (all Jung Types can be a 7).
Type 8: INFP, ISFP, ISFJ; Fi, Fi-n, Fi-s.
Type 9: N/A (all MBTIs can be 9s); Te-n and Ne-t.
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 Judger, or borderline J/P. Borderline or clear preference for Thinking is very likely, but not a must, same for Sensing.
Type 2: Must be a clear Feeler, or borderline F/T. Must be a clear Extravert, or borderline E/I.
Type 3: Must be a clear Extravert, or borderline E/I. Borderline or clear preference for Thinking and Judgment is quite likely, but not a must.
Type 4: Must be a clear Feeler, or borderline F/T. Must be a clear Introvert, or borderline I/E. Significantly more likely to be an Intuitive type, but that is far from a must.
Type 5: Must be a clear Thinker, or borderline T/F. Must be a clear Introvert, or borderline I/E.
Type 6: No restrictions, but way more likely to be a Sensor.
Type 7: Must be a clear Perceiver, or borderline P/J. Must be a clear Extravert, or borderline E/I.
Type 8: Must be a clear Judger, or borderline J/P. Must be a clear Extravert, or borderline E/I.
Type 9: No restrictions, but more likely to be an Introvert.
Just for the end of the post, it is good to notice that in self-report tests you can report yourself as 2 different persons to arrive with any profile including the contradictory combos, but that would be bad self-report. Actually, some people do it without being aware of that – me, for example, already self-reported to be highly excitable and not appreciate much excitement in the same day in different tests, but at least that was a minor that only affected facets rather than type. And another thing to be said is that some people like to rip off the descriptions of the enneagram and only evaluate fear, desire and the most basic word related. Well, with that in fact the restrictions changes and I’m considering the descriptions, desires and fears, when the desires and fears evoke anything MBTI or Jung related. But without the descriptions, the enneagram profiles changes, and actually that exposures a sort of enneagram flaw, and one example is Type 1. Being quick and resumed, Type 1 without the type descriptions lacks the dogmatism (the dogmatism of 1s can be deducted by the type descriptions, even though dogmatic here isn’t black and white so some 1s won’t be particularly dogmatic), and allows room for a clear moral sentimentalism. Actually, some or maybe even a lot of Fi-doms and INFPs has the fears and desires of 1s (specially if you pay attention at descriptions which put emphasis that INFPs are full of values), yet they don’t fall into the 1 profile but rather 4 because their moral type is moral sentimentalism and not dogmatic, they might have a strong sense of right and wrong but they might be more merciful and not rational at all. So, yeah, ignoring the profile descriptions makes the types more loose to combos yet it makes them more vague as well – and, about that, if you read a very vague type description of each type on the impossible combos that can allow any sort of combination.
And my restrictions are not absolute but I’m pretty confident my arguments are strong in general.
Typology Triad 
This all makes sense but in the real world, strange things happen. I am an ESTJ enneagram 4w5. It may have to do with severe trauma I experience throughout childhood. But I am indeed both.
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