The Spruce Carpet (Thera britannica) is a species of moth in the Geometridae family.
Its wingspan is about 30–36 mm. It is a double-brooded species, meaning it has two broods in one year. Its wings are colored with different shades of gray, but the spring brood tends to have more brown colors. It is attracted to spruce trees.
Its flight periods are April to late June (spring brood) and from the end of August to mid October (autumn brood).