If a ring is too tight or too wide, a professional can stretch out the metal, for example, or work on shrinking it with a machine. In case of a major difference, it is also possible to add or remove a piece of the band material. Cost varies drastically depending on the metal the ring is made of, how much of it needs to be sized, and how design elements of the ring will affect the new size. And, even experienced jewelers can make mistakes, so take your time, measure wisely and choose a trusted professional. It could be anywhere from $20 to hundreds of dollars to resize a ring, depending on these and other factors.