Ring Size 8 — Diameter, Circumference & International Conversions
Size 8 is the entry to the larger half of the women's range and the smaller half of the men's — a common women's size and a slim men's size. Here is exactly what it measures and how it converts everywhere.
Quick answer: US 8 = 18.13 mm inside diameter = 56.9 mm circumference = UK P½ = EU 57 = French 16.9 = German 18 = Japanese 16. Add a quarter (8¼) for bands 6 mm wide or wider. Slightly above the women's average, just under the men's.
Size 8 in every unit and system
- Inside diameter: 18.13 mm (1.81 cm)
- Inside circumference: 56.9 mm (5.69 cm)
- UK P½ · EU/ISO 57 · French 16.9 · Italian 17 · German 18 · Japanese 16
- Neighbours: 7¾ = 56.3 mm · 8¼ = 57.5 mm circumference
Who wears a size 8
For women it is a step above the 6–6.5 average — common in taller or larger-framed wearers and anyone whose dominant-hand ring finger runs large. For men it is the slim end of the normal band (8–12).
Buying a size 8 wide band
A 6 mm-plus band in size 8 grips like a plain 8½, so the correction matters: measure, then add a quarter for wide bands — order 8¼ for a 6–8 mm band, 8½ if you measured at the large end of 8 and the band is 8 mm or wider. Narrow dress rings under 3 mm need no correction.
Fit check for a size 8
The ring should pass the knuckle with slight resistance and settle at the base. Rotation test: a little spin is normal on tapered fingers; free spinning means go down a quarter. Soap test: if it slides off with hand soap alone, it is half a size too big.