Consciousness and calculation are two concepts that are perhaps related, but are often confused and merged together in both popular conception, and in academic and philosophical writing on consciousness, neurology and related fields.
Calculation is the ability of a system to come to an answer by applying rules to data. Consciousness is the qualitative feeling of experiencing.
It is taken for granted in some forms of pop neurology that we are conscious because it better allows us to calculate. The thought is that as animals developed more complicated behaviors and had to adapt to more diverse environments, they needed consciousness to calculate the answer to more and more complicated and diverse problems. A sea anemone requires no consciousness to filter particles out of the water, while a primate must consider whether a tree with juicy fruit might also hold a snake, and thus must have a greater amount of consciousness to calculate what the most desirable course of action is.
While this makes sense at first, since one of the main features of consciousness is the fact that it is deliberative, that it can hold multiple thoughts or plans, and choose between them. But there is no obvious reason why any level of calculational complexity requires consciousness. A simple calculation can be done without consciousness, and there is no reason why a more complicated calculation requires consciousness. The calculation process should be the same whether it is working with two factors or two thousand, and positing the necessity of consciousness to somehow put its fingers on the scales seems to be unnecessary.
Conversely, there could be (and are) conscious experiences that are immediate sensations, without requiring, or leading to, calculations. The smell of mint or the feel of an icecube are both sensations that are singular representations in consciousness, which are not the result of calculation (although they can, of course, lead to calculation or deliberation).
So while we often equate consciousness with calculation, there are counter-examples that show the two might not always be linked. For example, from my past few experiences with CAPTCHA images, my ability to calculate the true value of a string of distorted text is now roughly equivalent to that of an Artificial Intelligence. Yet I am conscious, and (presumably) the AI is not. Conversely, there can be consciousness without calculation being an element.
Of course, the common sense view that consciousness is somehow related to the need to calculate complicated problems, that it is necessary for deliberation, makes a lot of sense, and there are probably many justifications for it. However, to accept it as a given is a mistake.