Is "The Cold Equations" sci-fi?

I would say that "The Cold Equations" definitely falls under the category of science fiction. In fact, most, if not all, of Tom Godwin's writing is science fiction.
The literary genre of science fiction is based around advances in technology and scientific knowledge, and the impact of these advances on people, society, and the environment. It is very common to see space- and time-travel in sci-fi. Tom Godwin's short story "The Cold Equations" was first published in 1954, years before humans had done any sort of travel through space. The plot of the story is dependent on the possibility of space travel—Barton and Marilyn are traveling inside a ship through space, and the human race has done so much space exploration that humans are now living on other planets besides Earth.