European Ring Sizes to US — Complete Conversion Chart for Ordering Online

By Dmitry Strugovshchikov, founder of STRUGA

Two scales, one ring. Europe counts the millimetres around the inside of the band, which is why the number is large: 54, 57, 60. The US counts an index tied to inner diameter, which is why the same three rings read 7, 8 and 9. Below is the conversion in both directions, with the inner diameter in millimetres beside every row — the one figure that stays the same whichever chart you are reading, and the one you pick when you order from us.

What is a European ring size?

A European ring size is the inner circumference of the ring expressed in whole millimetres. A ring marked size 54 has an inner circumference of 54 mm, and a ring marked 60 has 60 mm. The system is linear, transparent, and used across Germany, France, Spain, Italy, the Netherlands, Scandinavia and most of continental Europe.

This is the cleanest sizing system on the market, and there is no arbitrary number, no fractional size, no historical drift. If your finger has a 56 mm circumference, you wear EU 56; and that is it.

The UK, Ireland, Australia and parts of the Commonwealth use a letter system (A–Z). The US, Canada, and Mexico use the numeric scale that runs from roughly 3 to 14 in half steps. Japan uses its own number scale, again different, and most of our customers at STRUGA order from the EU or the US — so this guide focuses on those two.

Why do European and US ring sizes use different numbers?

Because they measure different things, and Europe measures circumference (the distance around the inside of the band). The US scale, in contrast, started as a fractional inch system tied to inner diameter, and it was later standardised but never reformed. The numbers stuck.

Practically: a US size 7 sounds like a small number; an EU size 54 sounds large. They describe the same ring. The only thing that matters when you order online is the millimetre measurement underneath — inner diameter or inner circumference. Everything else is a label.

The two scales also round differently, and that is worth knowing before you compare sources. Europe rounds the circumference to a whole millimetre; the US scale rounds the diameter to a half size. The two therefore land 0.1–0.2 mm apart on the same finger, which is why two honest charts can disagree by a tenth of a millimetre — and why that tenth never decides a fit.

If a seller cannot tell you the inner diameter in millimetres, the seller does not know the ring well enough. That is one of the basic checks we recommend in our ring sizing notes.

European to US ring size conversion chart

Below is the full conversion table for ring sizing across European, US, and UK systems, anchored to inner diameter in millimetres. Use this as your reference when ordering any silver ring online — including from our oxidized silver rings page.

EU size (circumference, mm)	Inner diameter (mm)	US size	UK size
44	14.0	3	F
45	14.3	3¼	F½
46	14.6	3¾	G½
47	15.0	4	H½
48	15.3	4½	I½
49	15.6	5	J½
50	15.9	5¼	K
51	16.2	5¾	L
52	16.6	6	M
53	16.9	6½	N
54	17.2	7	N½
55	17.5	7¼	O
56	17.8	7½	P
57	18.1	8	P½
58	18.5	8½	Q
59	18.8	8¾	R
60	19.1	9	R½
61	19.4	9½	S½
62	19.7	10	T
63	20.0	10¼	U
64	20.4	10½	U½
65	20.7	11	V½
66	21.0	11½	W
67	21.3	11¾	X
68	21.6	12	Y
69	22.0	12½	Z
70	22.3	13	Z+1
71	22.6	13¼	Z+2
72	22.9	13½	Z+3
74	23.6	14	Z+4
76+	24.2+	14½+	Z+5+

The most common adult sizes cluster between EU 52 and EU 64 (US 6 to US 10½). Roughly 70% of orders we ship from our dark minimalist rings collection fall inside that band.

What size do I order from STRUGA?

STRUGA rings are not ordered in EU or US numbers. The size selector on every ring lists inner diameter in millimetres, and the range runs 15 to 22 mm — the same anchor the chart above is built on. Measure the diameter, round to the nearest whole millimetre, and that is the figure you choose at checkout.

The same number is the ring size used in Russia and across the CIS, where the size is simply the inner diameter: a Russian size 17 ring is 17 mm across the inside.

Inner diameter (mm) — the size you order	EU size	US size
15	47	4
16	50	5¼
17	53	6½
18	57	8
19	60	9
20	63	10¼
21	66	11½
22	69	12½

A millimetre step is coarser than a US half size, so each row is the nearest match rather than an exact equal. Two rings — Brutalism V.1 and V.3 — start at 15 mm; the rest of the ring lineup runs 16 to 22 mm. Anything outside that range is made to your measured millimetre figure through Custom Order.

How do I convert a US ring size to European?

Backwards from the US number: multiply the inner diameter by 3.14 and round to a whole millimetre. US 7 is 17.3 mm across the inside, 17.3 × 3.14 = 54.3, so US 7 is EU 54. The table below has it done for every half size from US 4 to US 13.

US size	Inner diameter (mm)	EU size
4	15.0	47
4½	15.4	48
5	15.7	49
5½	16.1	51
6	16.5	52
6½	16.9	53
7	17.3	54
7½	17.7	56
8	18.1	57
8½	18.5	58
9	19.0	60
9½	19.4	61
10	19.8	62
10½	20.2	63
11	20.6	65
11½	21.0	66
12	21.4	67
12½	21.8	68
13	22.2	70

The European scale steps in whole millimetres of circumference, which is finer than a US half size, so one EU number can sit between two US marks — EU 63 reads as US 10¼ going one way and US 10½ coming back. When the two columns disagree by a quarter step, read the diameter and ignore both labels.

How to measure your ring size at home

You need either a ring you already wear, or a strip of paper. Both work and neither is perfect. Use both if you want certainty.

Method 1 — Measure an existing ring (most accurate)

Take a ring that fits the finger you plan to wear the new piece on. Use a ruler with millimetre markings. Measure the inner diameter — the distance straight across the inside of the band, from one inner edge to the other. Read it off in millimetres.

Match that number to the inner diameter column in the chart above, and if the diameter falls between two numbers, round up rather than down. A ring that is half a size too large can be felt; a ring that is half a size too small cannot be worn.

Method 2 — Paper strip

Cut a strip of paper about 8 mm wide and 100 mm long. Wrap it around the base of the finger you plan to wear the ring on. Mark the point where the paper overlaps. Lay the strip flat and measure the distance from the start to the mark — in millimetres. That number is your EU size directly.

Three rules. Wrap snug, not tight. Pull the strip past the knuckle once to confirm it will slide over. Measure three times across the day, take the average.

What to avoid

Do not measure first thing in the morning — fingers are smaller after sleep. Do not measure right after exercise, hot weather, salty food or alcohol — fingers swell. Do not measure cold hands. Do not use string; it stretches and gives a false reading every time.

What is the diameter of a US size 7 ring?

17.3 mm. This is the most common women's ring size globally and the median size we ship for women's rings at STRUGA.

If your finger measures about 17.3 mm in diameter, US 7 / EU 54 is your size; if it is closer to 17.8 mm, you are closer to US 7½ / EU 56.

What is the diameter of a US size 8 ring?

18.1 mm. This sits in the middle of men's sizing and the upper end of women's sizing.

For men ordering from our men's silver rings, US 8 is the lower edge of common adult male sizing — typical sizes run US 9 to US 11. For more on choosing a first men's ring, see our guide on how to choose a men's silver ring.

Wide bands need a different size — Here is why

A 2 mm wedding band and a 12 mm brutalist statement ring at the same nominal size will not fit the same finger the same way. The wider the band, the more skin it covers, and the more it resists sliding over the knuckle. The same finger that takes a US 7 in a thin band may need US 7½ or even US 8 in a 10 mm band.

STRUGA rings tend to run wide, and many pieces in the BRUTALISM family sit between 7 and 12 mm, and the signet rings have a wide top face that adds rotational mass. For both, we recommend ordering half a size up from your standard band size.

At the other end of the range sit the chain rings. The Signature Links V.1 Ring is 2.7 g of 925 silver at size 16 and 4.0 g at size 22 — chain links joined into a single line around the finger, with no ornament, no stones and no added mass.

Stacking is a separate calculation. If you plan to wear three rings on one finger, the cumulative width is what the knuckle feels. Three 4 mm bands stacked behave like a single 12 mm ring on the knuckle.

Common conversion mistakes

The first mistake is reading the size off a ring you wear on a different finger. Each finger on each hand has its own size. The dominant hand tends to run a quarter to half a size larger.

The second mistake is assuming that a ring marked "M" or "7" or "54" on one brand fits the same as on another. Manufacturing tolerances vary by up to 2 mm off the nominal mark — which is part of the signature of handwork, as we discuss in our sterling silver guide.

The third mistake is converting from UK letters by guessing. Always use a chart. UK sizing increments are not aligned with EU millimetre increments, and the rounding direction varies by source.

The fourth mistake is ordering the size you wore at fifteen. Hands change with age, weight, climate, and time spent at the gym. Re-measure every few years.

If you are between two sizes, which way should you round?

Round up. Always. A ring that is slightly loose can be worn with a silicone spacer, resized by a local jeweller, or lived with until the finger swells in summer. A ring that is slightly tight cannot be slid over the knuckle, and forcing it leads to skin damage and stuck rings that need professional cutting to remove.

The exception is wedding bands and particularly thin pieces (under 3 mm) that you will never remove. These should fit snug. For statement rings, everyday-wear pieces and anything from the CODEX rings world, round up.

Ordering silver rings online — What to check before you click buy

• The millimetre figure. The product page should list inner diameter in millimetres beside the size. If it says only "size 8" with no millimetres, ask the seller before you order.
• The band width. Anything from 8 mm up needs the half size described above.
• The alloy. 925 sterling silver, carrying a 925 hallmark — one of the two authenticity checks we use, alongside visible signs of handwork, explained on the Living Silver page.
• The return and resize policy. Plain bands can often be resized; cast pieces with deep texture or set stones frequently cannot. STRUGA offers one exchange within the stated window, and Custom Order pieces are produced to your size and are final.
• The moment you measure. Skin shrinks in cold rooms and on long flights. If your hands feel cold or dehydrated, wait a day.

What if my size is not on the standard chart?

Sizes below EU 44 and above EU 76 are uncommon but real. We produce rings outside the standard chart through Custom Order, and matched paired rings outside it through Dark Union, for couples whose sizes do not fit the off-the-shelf range.

For wedding and paired pieces in non-standard sizes, work with us through Dark Union (paired and wedding rings) or Custom Order (any individual form). Both routes start from your measured millimetre figure, not from a label.

After the ring arrives — First checks

Slide it on cool, dry hands. It should pass the knuckle with steady, gentle pressure and seat at the base of the finger without floating. Rotate it once around the finger. If it spins freely without resistance, it is too large. If it cannot rotate at all, it may be too small or your finger is swollen — wait twelve hours and try again.

Wear it for a full day before deciding. The first hour is misleading, because fingers adjust. The piece should be present but not painful. If it leaves a deep red mark that does not fade in fifteen minutes after removal, the size is wrong.

Once the size is right, the ring will start to live. Patina develops, edges soften slightly with wear, and the surface darkens in the recesses. To preserve the intended contrast, follow our oxidized silver care guide. To bring back brightness on highlights only, see how to clean a silver ring.