A jack with an optionally pivoting foot provides a trailer owner the ability to change between a wheel and a flat foot or a flat foot and a wheel upon a jack depending from a trailer tongue. The present invention has an optional foot attached to a jack that rotates from a horizontal position to underneath an existing foot. The foot has two parallel spaced apart flanges extending upwards from a base. The flanges have a bolt through a centered hole near the wheel about which the pivoting foot rotates. Opposite the base, the flanges have three holes about the perimeter through which a handle inserts. The handle secures the foot in either horizontal or vertical configurations. When in a vertical configuration, a wheeled jack does not move upon nor embed into the ground. A jack with a flat foot prevents a trailer from moving.