There are many reasons your ring may need to be resized, including you gaining weight, losing weight, injury or the ring being purchased in the wrong size. In most cases resizing a ring can easily be done by any trained jeweler. Soft metals such as gold, platinum, palladium and silver can be resized. However, if your ring is made of tungsten carbide it cannot be resized. Most rings will only be able to increase two sizes, as the metal will become too thin. If your ring needs to be sized down, this should also be sized two or fewer sizes down. Having your ring sized up or down only one size will give you the optimum outcome.

 
Instructions
 
First, take your ring to a reputable jeweler. If your ring was purchased with a warranty package, this may include free ring sizing for the life of the jewelry. If so, take your ring to the jeweler who sold it to you.
 
Next, place the ring sizer on the finger you plan wear your ring on. You may have to try two or three sizes to find the correct fit. Pick a size that is snug enough so that the ring won't fall off but still is comfortable to wear. You want to able to remove your ring when necessary. Your fingers will swell as the day goes on, it is best to get your ring sized in the middle of the day, when your fingers are at their average size.
 
Then, inform the jeweler on any engravings in the inside of the ring. Oftentimes when resizing a ring the engraving will be ruined. See if your jeweler can resize the ring without damaging the engraving. If the jeweler is unable to resize the ring without damaging the engraving, ask the jeweler re-engrave the ring.
 
Lastly, pick up your ring once the jeweler has notified you that it is done. This process often takes anywhere between one to four weeks depending on how busy the jeweler is, and how difficult the ring is to re-size. Be sure to try on your ring to make sure that it is the proper size. Examine the ring to make sure it is how you left it and that there have been no damage to the ring.