Ring Sizer Ring no longer goes over your knuckle: which size now?
Measure the knuckle width with Finger Sizer, measure the ring you own with Ring Sizer, and compare the two diameters in millimetres. The new ring has to be bigger than the knuckle, not the base of the finger.
Everyone says size at the base of the finger. That stops working when the knuckle is wider, and a ring that slid on once and now stops is that case. Two widths matter, knuckle and base, and the ring has to clear the bigger one.
Measure both places
- Calibrate first under Calibration if you have not. Without it every figure below is off.
- Open Finger Sizer. Lay the finger flat on the screen and widen the two bars until they touch the sides of the knuckle. Write down the diameter.
- Move the finger so the base is between the bars, and do the same. Write that down too.
- Open Ring Sizer, lay the ring that no longer passes on the screen and match the circle to its inside edge. That is the number you are replacing.
- Subtract: knuckle diameter minus the ring's inside diameter.
A knuckle is oval, so one reading from one side is not enough. Readings from above and from the side can differ by about a millimetre — use the larger.
Worked example
| Reading | Diameter | Circumference | US | UK |
|---|---|---|---|---|
| Ring that stopped at the knuckle | 17.2 mm | 54.0 mm | 7 | O |
| Knuckle width | 19.1 mm | 60.0 mm | 9 | S |
| Difference | 1.9 mm | 6 mm | 2 sizes |
So the size 7 was always going to catch, and the knuckle needs at least a US 9. Example numbers only, not a reading of any real finger.
What size to pick
If the knuckle is far bigger than the base, a ring sized for the knuckle will spin or slide off at the base. Buying the bigger number alone is not the fix. A narrower band helps, and a jeweller can add sizing beads or a hinge. The app measures; it does not pick a style.
One limit: the sliders do not know which part of the finger you are on, so nothing warns you if the two readings get mixed up. Writing each one down in order, as it's measured, avoids confusion.
Finger Sizer, Ring Sizer, Calibration and the converter are free. One saved measurement is free; more needs Premium or a short ad, two a day at most.
Questions and answers
Should you measure ring size at the knuckle?
How do I size a ring with big knuckles?
Can't get a ring over the knuckle anymore, is the ring smaller?
Is the on-screen reading exact?
You might also like
- Which finger to measure for your ring size · Ring Sizer
- How to measure your ring size at home with your phone · Ring Sizer
More Ring Sizer guides
- How to measure your ring size at home with your phone
- Find a ring size without asking, a jeweler or a ring sizer
- Ring size conversion chart: US, UK, EU and Japanese sizes
- Which finger to measure for your ring size
- Choosing a ring metal: gold, platinum, titanium and more
- Birthstone by month: a chart for all 12 months
- How to clean and care for a ring at home
- Compare two ring sizes: how big is the difference?
- Ring size in Mexico vs the US: how do you convert?
- Does your ring size change during pregnancy, and how can you track it?
- All questions about Ring Sizer
- Back to Ring Sizer