What type of anchors would be best to hang a 15 lb mirror?

Question

It has 2 D rings on the back and will be mounted on drywall but can't be centered on a stud.

Answer 1

Any hardware store will have just what your looking for.
They have anchors that are for specific weights.
Hope this helps.

Answer 2

Consider using what is called a cleat. A cleat is usually a piece of wood that is installed horizontally on a wall and acts like a bridge between two studs. The cleat supports the weight of what is being hung and transfers that weight to the studs. Thus, the dry wall is not used to support the object's weight. The problem with your mirror is that it might not be wide enough to hide the cleat. So, you can either change the mirror's location just enough to hide a horizontal cleat OR you can use a vertical cleat. Picture a vertical cleat to be like a badge pinned on a garment. The object is to distribute the mirror's weight over as much of the dry wall as possible by using several nails spaced over the cleat's area to attach the cleat to the dry wall. Concentrated weight of the mirror using the two hangers on the mirror's back is supported by the cleat. The cleat transfers that weight to the dry wall by using several nails driven through the cleat and into the dry wall. Space those nails so as to disperse the weight over the largest area possible. Be sure to drive all the nails in at an angle that will cause the weight to press the nail into the dry wall, i.e. head of nail pointed toward the ceiling. Sort of like place lawn sod with the green side up. :-)