Jewellery, gold and diamonds
How to measure ring size at home
Ring size is an inner diameter in millimetres; everything else is a label. Measure a ring you already wear, or the finger, and convert. Kubikly uses the millimetres directly to scale a model.
Method 1: a ring you own
Lay it on a ruler and read the inner diameter across the widest point to the nearest 0.25 mm. Photograph it beside a coin or a ruler and the studio measures it for you.
Method 2: the finger
Wrap a strip of paper around the base of the finger, mark where it overlaps, measure the length: that is the circumference. Divide by 3.14 for the diameter. Measure in the evening, when fingers are largest, and add 0.5 mm for wide bands.
Method 3: a sizer
Plastic sizer sets cost a few dollars and are the most reliable for a surprise. Order one size up and down and note the knuckle.
| Inner diameter | Circumference | US | UK | EU / ISO |
|---|---|---|---|---|
| 15.7 mm | 49.3 mm | 5 | J½ | 49 |
| 16.5 mm | 51.9 mm | 6 | L½ | 52 |
| 17.3 mm | 54.4 mm | 7 | N½ | 54 |
| 18.1 mm | 57.0 mm | 8 | P½ | 57 |
| 19.0 mm | 59.5 mm | 9 | R½ | 59 |
| 19.8 mm | 62.1 mm | 10 | T½ | 62 |
| 20.6 mm | 64.6 mm | 11 | V½ | 65 |
Why it changes the price
A size 9 band uses about 8% more metal than a size 6; a full eternity ring in size 9 takes three more stones than size 6. The model recomputes weight and stone count as you change the size, so the price follows.
Frequently asked
- What if I am between sizes?
- Go up for wide bands and for warm climates; go down for thin bands and if the knuckle is small.
- Can the studio measure my finger from a photo?
- No, fingers compress. It measures rings against a reference object; for a finger use the paper strip.
- Can a full eternity ring be resized?
- No. Get the size right in the model first; half eternities can be adjusted.
Keep reading
- Gold hallmarks explainedHow to read the tiny numbers inside a ring: 375 is 9K, 585 is 14K, 750 is 18K, 916 is 22K. What each is worth per gram today and how to check a piece with no mark.
- How jewellery is pricedWhere a jewellery price comes from, line by line: gold at spot, stones by size and grade, workshop hours, wholesale and retail margins, brand, and VAT per country.