Trothe Free ring sizer

Free tool

Ring size finder

Measure a ring you already own, or a strip of paper around the finger. The first method is more accurate, so it is the one we put first.

Lay the ring flat and measure across the inside, edge to edge. Most adult rings fall between 15mm and 22mm.

Still not sure?

We will post you a free ring sizer. No purchase, no pressure. It is a plastic gauge, it takes thirty seconds, and it is the only way to be certain without a jeweller. If a ring turns out wrong anyway, we replace it free.

Post me a free sizer

The full UK size chart

Inner circumference and diameter in millimetres, with US and European equivalents. European sizing under ISO 8653 is simply the circumference.

UKCircumferenceDiameterUSEU
A 37.8 mm 12.03 mm 0.5 38
B 39.1 mm 12.45 mm 1 39
C 40.4 mm 12.86 mm 1.5 40.5
D 41.7 mm 13.27 mm 2 41.5
E 42.9 mm 13.66 mm 2.5 43
F 44.2 mm 14.07 mm 3 44
G 45.5 mm 14.48 mm 3.5 45.5
H 46.8 mm 14.90 mm 4 47
I 48.0 mm 15.28 mm 4.5 48
J 48.7 mm 15.50 mm 5 48.5
K 50.0 mm 15.92 mm 5.5 50
L 51.2 mm 16.30 mm 6 51
M 52.5 mm 16.71 mm 6.5 52.5
N 53.8 mm 17.13 mm 7 54
O 55.1 mm 17.54 mm 7.5 55
P 56.3 mm 17.92 mm 8 56.5
Q 57.6 mm 18.33 mm 8.5 57.5
R 58.9 mm 18.75 mm 9 59
S 60.2 mm 19.16 mm 9.5 60
T 61.4 mm 19.54 mm 10 61.5
U 62.7 mm 19.96 mm 10.5 62.5
V 64.0 mm 20.37 mm 11 64
W 65.3 mm 20.79 mm 11.5 65.5
X 66.6 mm 21.20 mm 12 66.5
Y 67.8 mm 21.58 mm 12.5 68
Z 69.1 mm 22.00 mm 13 69

Sizing questions

What is the most accurate way to find a ring size at home?
Measure a ring that already fits the correct finger. Lay it flat and measure the inside edge to inside edge in millimetres. That inner diameter converts directly to a size and it is more reliable than any paper strip, because paper stretches and overlaps.
Does the time of day matter?
Yes, more than most people expect. Fingers are smallest first thing in the morning and after cold, and largest in the evening, in heat and after salt or alcohol. Measure late in the day at normal room temperature, which is closer to how the ring will be worn most of the time.
What if my knuckle is larger than my finger?
The ring has to pass the knuckle, so size to the knuckle and then choose a wider band, which sits more snugly on the finger behind it. If the difference is more than about one and a half sizes, tell us and we will adjust the profile rather than the size.
Do wider rings need a bigger size?
Usually half a size up from about 6mm, because a wide band covers more of the finger and has less room to flex over the knuckle. Our size finder applies this automatically once you tell it the width.
How do I find someone's size without asking?
Borrow a ring they already wear on the right finger and measure its inner diameter. Failing that, order a free sizer from us and choose a size later. Guessing from a photograph or a piece of string around a sleeping finger is how rings come back.