It has rough, dark grey, fibrous and flaky bark on the trunk, smooth greyish bark above, lance-shaped adult leaves, flower buds usually in group of three, creamy white flowers and cup-shaped to cylindrical fruit.

Eucalyptus platycorys is a mallee, rarely a small tree, that typically grows to a height of 2–12 mm (0.079–0.472 in) and forms a lignotuber.

The fruit is a woody, cup-shaped to cylindrical capsule with the valves at rim level or below it.

[5][6] The specific epithet (platycorys) is from ancient Greek, meaning "flat", "wide" or "broad" and "helmet", referring to the operculum that is wider than the hypanthium.

[2][3][4] This eucalypt is classified as "not threatened" by the Western Australian Government Department of Parks and Wildlife.