Is "it is no calculus" correct grammar?

I think you're probably looking for an idiom like

It's not rocket science.

or

It's not brain surgery.

or, as some wags have it,

It's not rocket surgery.

This is one of those cases where modifying a cliché to make it fresher doesn't quite work. Saying "It's not calculus," while reasonable in a certain context, would not have currency among the general population and would not be readily understood to mean something easy or inconsequential.

EDIT: I answered with "not" constructions because I figured the OP would accept any negative construction, and as Scott Mitchell points out in his comment "not" certainly works better than "no" in the OP's example.

I would not risk using "It is no calculus". You might be meaning "It is not as hard as (differential or integral) calculus", in which case, say so. Or you might be referring to a logical system and stating "That isn't a calculus; it is merely an algebra", in which case, say that instead. Your original is ambiguous, therefore (at least, without the larger context to guide us), and probably too informal for a college essay.

It would depend on context. This is certainly no idiom.

… that I am familiar with.