What IQ is required to be an engineer?
The estimates given by Stan V for a Junior Engineer seems about right as a starting point. I will say that IQ might not even be the best metric to use here. I would rather think about this question from a skills perspective. Give me the specific engineering field and then we can determine the required skills To do well in these skills will generally require a certain level of intelligence. If your goal is to become a senior engineer who manages large teams of people effectively, then you better also have at least adequate people skills. Also, some countries might be more selective than others depending on domestic needs and the overall talent pool.
Finally, across professions, IQ has been drifting higher due to automation and telecommuting. With the explosion in AI capability in the past 5 years, I expect this trend to accelerate. Here is a real life example on how technology has impacted my field. Recently, I was involved in a massive analytic effort to evaluate a $10 to $50 B company that was recently sold. At the start of my career in the mid 90’s the team would have been at least twice as large and located in one or two cities with a single staff member assigned to each asset location. Pack your bags, you are spending the next two months in xxxx. In 2015, we were able to handle a large number of the meetings via teleconference or advanced teleconferencing. As a result, no one had to visit a warzone, and the corporate team in South America was so on the ball that we felt comfortable handling everything remotely. The staffing of the project took place from 5 separate offices scattered through the NA and Asia.