Baseboard molding installations are very often finished off with a small piece of molding that covers the gap between the bottom of the baseboards and the floor. Two types of molding can be used here: shoe moldings (also called base shoe, or 1/8-round molding) or quarter-round molding. Shoe moldings and quarter-round moldings look very similar, but the quarter-round is a slightly larger piece—a full one-quarter of a round dowel.
Shoe moldings or quarter-round are not always a part of the baseboard installation. With ranch moldings and other small baseboard moldings, they are often omitted. Shoe or quarter-rounds are more commonly used with larger, more substantial baseboards, especially those that are built-up with cap moldings at the top. Trim carpenters like to use these bottom trim pieces because they give the project a crisper finished look, and they also reduce the need for complicated baseboard cuts. These bottom moldings can also help hide flaws in the flooring installation since they cover up the gaps at the bottom of the baseboard.