The number of magazines that your wall-mounted metal magazine rack can hold will depend on the number of cubbies or pockets that your rack has. You can figure that each pocket will hold between 1-3 magazines, depending on the size of the pocket and the width of your magazine.
If your rack is smaller and only has one pocket, you’ll only be able to hold a few magazines. Larger magazine racks with 10-20 racks will naturally be able to hold many more.