Abstract: An adjustable wrench or spanner is disclosed. It comprises essentially an elongated handle element with a convex urging portion at one end, an upper jaw element with a concave urging portion, a lower jaw element with a protrusion portion and a ratchet assembly. The upper jaw element is movable with the assistance of the two engaging urging portions and the lower jaw element is adjustable with the assistance of the ratchet assembly. Two jaw portions are operable in tightening or loosening positions, without having to be disengaged from a hexagonal nut. When the jaw portions are opened in a loosening position, gripping edges of the jaw portions are allowed to shift from one width across flats to another width across flats.