European and US ring sizes: conversion chart and measurements

By Dmitry Strugovshchikov, founder of STRUGA

EU 54 means an inner circumference of 54 mm: its calculated diameter is 17.19 mm. A Russian size describes diameter.

EU 54 is often sold as US 7, but this is an approximate match. Tiffany lists US 7 at 17.3 mm diameter and 54.4 mm circumference.

Use the seller’s chart before ordering. Keep the measurement, sizing system and band width together when asking about fit.

Updated October 17, 2026

What does a European ring size measure?

In a circumference-based European chart, the number describes the inside of the ring in millimetres. EU 54 therefore means 54 mm around that opening. It does not mean a diameter of 54 mm. A Russian size uses the other measurement: size 17 means an internal diameter of 17 mm. SOKOLOV’s sizing guide explains this diameter convention.

On the Signature Links V.1 Ring, the size selector is labelled “Inner diameter (mm)”. Keep the measured diameter beside that option: an EU circumference label cannot be entered as the same number.

The two measurements are connected by circumference = π × diameter. Dividing 54 by π gives 17.19 mm, rounded to two decimal places. For EU 60, the corresponding calculation gives 19.10 mm. These are geometric conversions for a circular opening, rather than promises about how a particular ring will feel.

• Keep the unit beside the number: circumference in mm or diameter in mm.
• Ask which system a seller means when a listing says only “size 17”.
• Keep the original measurement before rounding it to an available option.

A sizing label describes an opening. It cannot replace a fit check on the intended finger.

European to US conversion: one named chart

The following dimensions come from Tiffany’s official size guide, checked on October 9, 2026. They are rounded values from that brand’s chart. The circumference column helps compare a European label with a US option; it is not a column of exact integer EU equivalents.

Use the nearest row as a starting point, then confirm with the seller. An opening with an exact circumference of 54 mm falls near Tiffany’s US 7 row. The listed circumference there is 54.4 mm. Calling those two measurements identical would hide the rounding. Another jeweller’s chart may assign the nearby measurement differently, especially around quarter sizes.

How to translate a US size back into millimetres

Start with the diameter or circumference in the chart used by the seller. A US index is not a millimetre measurement. Multiplying the index itself by π does not produce a usable European size. With a stated diameter, multiply that diameter by π; with a stated circumference, keep it directly.

US 7 and US 8 as worked examples

• US 7 in the named chart: diameter 17.3 mm, circumference 54.4 mm.
• US 8 in the same chart: diameter 18.1 mm, circumference 57.0 mm.
• EU 54 calculated geometrically: diameter 17.19 mm, not exactly 17.3 mm.
• EU 63 calculated geometrically: diameter 20.05 mm, before any shop-specific rounding.

Do not convert a rounded EU result back into US and expect the original label every time. Each rounding loses information. Keep the original chart and measurement when comparing two offers. If one seller gives only a size label, ask for its measurement and chart before deciding.

Russian, Italian and French labels: check the scale

A Russian diameter size and an EU circumference size are different numbers for the same opening. A diameter of 17 mm corresponds geometrically to 53.41 mm circumference. A diameter of 18 mm corresponds to 56.55 mm. A seller may round these to a whole EU number, but the unrounded measurements remain useful.

Country names alone do not identify a sizing system. The CaterinaB guide places Italian 14 beside French 54, and Italian 20 beside French 60. That is why this article does not describe every Italian number as circumference in millimetres.

• For a Russian number, confirm that it means internal diameter.
• For an EU or French number, inspect the circumference column.
• For an Italian number, use the chart supplied with that ring.
• For a UK letter, use a named UK conversion chart.

Do not silently treat a combined “US/UK” numerical column as a UK letter scale.

Measure a reference ring before choosing a label

A ring that already fits the intended finger gives a useful reference. Measure the opening straight across its centre, from one inner edge to the other. Record the internal diameter in millimetres. Outer diameter includes the metal and answers a different question. A distorted or oval opening also needs more care than a simple circular calculation.

Use a finger gauge or a jeweller’s fitting when the home measurement is uncertain. ISO 8653:2016 concerns ring-size measurement with a ring stick and consumer finger gauges. Its public catalogue description supports those measuring methods; the full standard has not been reproduced here.

• Choose a reference ring worn on the same finger and hand.
• Read the inner opening rather than the outside edge.
• Keep the measured value before choosing a rounded size.
• Confirm print scale if using a downloadable measuring sheet.

For the practical measuring sequence, use our ring size guidance. This conversion chart helps interpret the result.

Why a wide ring needs its own fitting

The chart translates dimensions; it does not calculate a universal correction for band width. A broad band and a narrow band with the same opening can feel different. The ring’s profile, inside edge and intended wearing position matter alongside its labelled size. A fixed instruction to add half a US size for every wide ring would erase those differences.

Bulgari’s fitting guide provides design-specific advice for its own rings. That is a useful reason to seek advice for the exact model, rather than carrying an adjustment from another brand into the order.

• Tell the seller whether your reference ring is narrow or broad.
• Ask for the width of the band on the model you want.
• Try that model, or a comparable gauge, when the opportunity exists.
• Discuss several stacked rings as a combined fitting situation.

For a BRUTALISM ring, discuss the particular form. Do not choose a different size solely because the collection name suggests a heavy object.

Between two sizes: confirm the available options

Two adjacent labels can bracket your measurement without either being an exact match. That is a reason to check fit and available options, rather than automatically rounding a whole millimetre upward. A whole millimetre of diameter is a larger change than a whole millimetre of circumference.

Send the original measurement and the model together. Keep the reference ring’s width in the message. If the result came from paper, say so; it carries different uncertainty from a finger gauge. Bulgari advises measuring under appropriate conditions and following its own guide when a result falls between sizes.

• Do not average labels taken from unrelated brands’ conversion charts.
• Do not round diameter first and circumference again afterwards.
• Do not borrow a friend’s size for a different finger.
• Ask about fitting, available increments and exchange before payment.

A useful reply names the offered size and its measurement. Save that reply with the order so there is a clear reference later.

Buying silver rings in Bali or ordering online

For the international market, STRUGA objects are made in Bali.

When buying silver rings in Bali, confirm the shop’s sizing system before choosing a number. Location alone does not tell you whether a chart uses US labels, circumference or diameter. If you can visit, try the exact ring and ask how its size is recorded. For an online order, provide the measurement and the hand and finger it is intended for.

• Confirm the size system and the measurement behind the offered option.
• Check the band width and whether the inside profile differs from your reference.
• Ask whether that exact model can be adjusted.
• Read the exchange terms for the order and destination.
• Confirm any custom specification before approving manufacture.

Explore STRUGA’s silver rings after establishing the measurement. For a matched pair, the Dark Union collection gives a separate route. Discuss each wearer’s size independently. A custom order needs its own confirmed dimensions; an approximate conversion alone is not a finished specification.

Before and after the order: keep a clear reference

Check fitting and service terms for the particular order. Resizing is a question about the exact design. It is not guaranteed by the word “silver”. A textured surface, construction or setting can affect what an adjustment involves. Ask before ordering when that option is essential.

On arrival, compare the delivered size with the size recorded in the order. Try the ring without forcing it over the joint. If it pinches, feels loose or differs from the confirmed specification, contact the seller with the model and measurements.

• Keep the confirmed size, system and measurement together.
• Record the order’s exchange and custom-order conditions.
• Describe any fitting concern before arranging an alteration.
• Ask the maker about an adjustment to the particular design.

Our contact page is the next step for a sizing question. For surface maintenance once the fitting is settled, see the oxidized silver care guide.