Why fit matters
A ring that is too loose can slip off, while one that is too tight is uncomfortable and hard to remove. Getting the size right makes a ring something you forget you are wearing.
Fingers are not a fixed size. Fit is best treated as a range that feels secure but not squeezing.
Measure from a ring you already own
If you have a ring that fits the intended finger well, it is the most reliable starting point. A jeweler can measure its inside diameter directly.
Be sure the ring is worn on the same finger and the same hand. Fingers on the dominant hand are often slightly larger, and a ring worn on a different finger will mislead you.
String and paper methods
You can wrap a thin strip of paper or a piece of string around the base of the finger, mark where it overlaps, and measure its length. This is a handy rough guide, but it has real limits.
String stretches, paper creases, and it is hard to account for the knuckle. Treat the result as an estimate and not as an answer.
What changes the fit
Wide bands tend to fit tighter than narrow ones because more of the finger is covered. Many people go up slightly for a wide band, and a jeweler can advise on how much.
Knuckles matter too. If your knuckle is larger than the base of your finger, the ring must clear the knuckle yet still stay put, which sometimes calls for a size in between or an adjustable fit.
- Temperature: fingers swell in heat and shrink in cold, so avoid measuring right after exercise or in a chilly room
- Time of day: fingers can be slightly larger later in the day
- Salt, humidity and certain medications can also change how fingers feel
Get measured professionally
Before ordering, have your finger measured by a professional jeweler using proper sizing tools. They can check both the knuckle and the base of the finger, and can account for band width.
Measuring at a couple of different times of day gives the most reliable result. A little care at this stage can save the effort of resizing later.