Clypeaster humilis is a medium-sized species of sea biscuit, growing to a maximum length of 160 mm (6 in).

The individual petals are closed and the petaloid area occupies less than half the width of the test.

The oral (under) surface is somewhat concave and the food grooves are long and deeply incised.

When living, this sea biscuit is greenish-grey or brownish, the petaloid area sometimes being darker brown; the bare test is yellowish or beige.

[2] This species is found in the western Indo-Pacific region, its range extending from the Red Sea and Persian Gulf to Malaysia, New Caledonia and northern Australia.