I received a series of questions from a reader with no return email. So if you’re reading this, Carl, I’ll answer your questions in the blog. Starting with this – what is the difference between complex and complicated? A plan, for example, can be both complex and complicated. There is a simple answer and a complicated (or complex!) answer. So let’s start with the simple: complex involves many parts/components, while complicated refers to the level difficulty. What does this mean in practice?

Examples that highlight the difference between Complex vs Complicated

Complex essentially refers how much (i.e. a lot is going on) while complicated refers to how difficult (i.e. how hard is it). In many cases this can lead to two phrases with the same basic meaning, as complex can be inferred to mean difficult.

A plan could be both complex and complicated, and either might be roughly understood as a difficult plan. However, to be accurate the use of complex is specific to its level of detail – in this case, if the plan is interpreted as difficult, it is because it has a lot of components. What we are really saying is just that it has many components, difficult is an interpretation of that. A complicated plan, meanwhile, may be difficult because it has a lot of components, but it may also be difficult simply because it has not been explained properly. What we are saying with complicated is that it is difficult because of it has many details, but that detail is not necessarily due to it having many parts – it could also be due to other factors (such as external influences).

Complex and complicated arguments is another example. The two sentences below might be interpreted the same way (a difficult or detailed argument), but the note in brackets shows a more accurate interpretation.

• “He developed a complex argument.” (The argument had many different details, perhaps covering a lot of angles and considering different viewpoints.)
• “He developed a complicated argument.” (The argument had many different details that were perhaps hard to follow.)

With a practical system, such as in healthcare or a school, the difference becomes more apparent. A complex school system would be one that has lots of different parts (for example multiple teachers, locations, subjects, exams etc.) while a complicated school system would be one that is hard to follow (it may have the same different parts as before, but the implication is that it is hard to explain).

Internal or external factors?

A good thing to consider is that complex often refers to a more internal state, owned by the object. (a complex object has many parts) while complicated may refer to more external conditions, not necessary owned by the object (a complicated object may be affected by external influences.

For example, a complex building is one with lots of different parts (for instance many rooms or annexes). A complicated building might be one that has a difficult history or diverse uses (for example because it has been affected by adverse regulations).

Again, a complex or complicated building could be used to give the same basic meaning, until you add more detail:

• “It was a complex building, because it had twenty rooms, four lifts and a sky bridge.”
• “It was a complicated building, because we had to negotiate the council’s zoning restrictions.”

I hope this goes some way to clarifying the difference between complex and complicated – I could go on but don’t want to go overboard with it! Let me know if you have any questions in the comments below. If you enjoyed this article be sure to check out other commonly confused words.