Catbird ring size guide

Catbird uses US sizes. Its guide recommends the larger size when between sizes and considering an extra half size for wide bands.

US sizing system

7 starter value

2026-10-20 source review

Published charts cross-checked
No sign-up
Mobile-first
Reviewed sources

I know my size in Value

Your size is US 7 (UK N½, EU 54).

Measurement check Exact table match

Measurement check Standard chart conversion; final fit still depends on band width and knuckle shape. Confirm with a printable or physical sizer before ordering an expensive ring.

17.32 mm Circ mm 54.4 mm

US: 7
UK: N½
EU / ISO: 54
Japan: 14
CH / IT / ES: 14
Inner diameter, millimetres: 17.32
Circ mm: 54.4

Why this size?

Your input maps to US 7 — UK N½, EU 54, JP 14, Ø 17.32 mm.

Calculated dimensions are rounded chart values, not a measured accuracy guarantee. Ruler placement, print scale, screen calibration and the finger can change the result. Confirm with a physical sizer before ordering.

Open US 7 size guide

More options

Print Smart rings Brand guides Wallet Screen sizer Between sizes Wide-band fit

Local only; no account.

Ring fit fix advisor

Choose the fit problem and get the safest next step before resizing, replacing or buying another ring.

Too tight or stuck Too loose or spinning Wide band or comfort-fit Non-resizable or brand ring

Converter chart
US	UK	EU	JP	CH	Inner diameter, millimetres	Circ mm
3	F½	44	4	4	14.07	44.2
3.5	G½	45	5	5	14.48	45.5
4	H½	47	7	7	14.88	46.8
4.5	I½	48	8	8	15.29	48.0
5	J½	49	9	9	15.70	49.3
5.5	K½	51	10	11	16.10	50.6
6	L½	52	12	12	16.51	51.9
6.5	M½	53	13	13	16.92	53.1
7	N½	54	14	14	17.32	54.4
7.5	O½	56	15	16	17.73	55.7
8	P½	57	16	17	18.14	57.0
8.5	Q½	58	17	18	18.54	58.3
9	R½	60	18	20	18.95	59.5
9.5	S½	61	19	21	19.35	60.8
10	T½	62	20	22	19.76	62.1
10.5	U½	63	22	23	20.17	63.4
11	V½	65	23	25	20.57	64.6
11.5	W½	66	24	26	20.98	65.9
12	Y	67	25	27	21.39	67.2
12.5	Z	68	26	28	21.79	68.5
13	Z½	70	27	30	22.20	69.7

How Catbird sizing works

Confirm the specific style; there is no universal quarter-size rule for thin rings.

Fast conversion anchors

These are approximate rows from the Ringsizely converter, not the manufacturer’s official size chart or a list of sizes sold. Check the linked brand guide for its own measurements, available sizes and model-specific fit.

Fast conversion anchors
US	US	UK	EU
6	6	L½	52
7	7	N½	54
9	9	R½	60

Wide-band size calculator

Estimate the order size for a wider band, then confirm before buying a non-resizable ring.

This advisor uses editorial rules to suggest sizes to try. Its adjustments have not been validated by a wearer study and are not manufacturer sizing instructions. Compare the same width and inner profile with a jeweler.

Normal US size Band width: 6 mm Fit preference Knuckle shape

Sources checked for the scope described here. Tool adjustments are editorial estimates, not measured fit outcomes or retailer quotes; specialist and native-language sign-off remain separate.

Generic conversion reference

Generic conversion reference
US	UK	EU	Inner diameter, millimetres
3	F½	44	14.07
3.5	G½	45	14.48
4	H½	47	14.88
4.5	I½	48	15.29
5	J½	49	15.70
5.5	K½	51	16.10
6	L½	52	16.51
6.5	M½	53	16.92
7	N½	54	17.32
7.5	O½	56	17.73
8	P½	57	18.14
8.5	Q½	58	18.54
9	R½	60	18.95
9.5	S½	61	19.35
10	T½	62	19.76
10.5	U½	63	20.17
11	V½	65	20.57
11.5	W½	66	20.98
12	Y	67	21.39
12.5	Z	68	21.79
13	Z½	70	22.20

Frequently asked questions

Does Catbird use US ring sizes?

Catbird uses US sizes. Its guide recommends the larger size when between sizes and considering an extra half size for wide bands. Confirm the specific style; there is no universal quarter-size rule for thin rings.

Ringsizely is an independent ring size converter and is not affiliated with, endorsed by, or sponsored by Catbird. Brand names are used for identification only. Always confirm with the retailer before ordering a non-resizable ring.