A complete Chinese ring size guide for 2026 — measure your finger or an existing ring, calculate the nearest China GB/ISO circumference size, compare international conversions and shop more confidently in mainland China.
Print at 100% or “actual size”. First measure the 50 mm calibration line with a physical ruler. Only use the circles when that line prints at exactly 50 mm. Place a comfortable ring over a circle and align the ring's inside edge—not the outside metal edge.
A 52 mm internal circumference points to standards-based size 52.
Example: 5.2 cm × 10 = 52 mm, giving size 52.
A 16.55 mm inner diameter gives approximately 52.0 mm circumference.
A 56 mm circumference gives an inner diameter of about 17.83 mm.
Do not convert by subtraction alone; domestic listings may use different numbering tables.
Provide circumference and diameter alongside US, UK or EU size to reduce conversion errors.
This calculator selects the nearest whole circumference size. If a Chinese product page shows a small “号” number rather than a 40–76 circumference size, match your millimetre measurement to that seller's own chart.
| 🇨🇳 China GB / ISO | ⭕ Circumference (mm) | 📏 Inner Diameter (mm) | ⭕ Circumference (cm) | 🇺🇸 US Approx. | 🇬🇧 UK Approx. | 🛒 Marketplace Label | Range |
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Select the finger on which the ring will actually be worn. Left and right hands can differ, and the ring finger may be a different size from the middle or index finger. Remove other rings and allow your hand to settle at a comfortable indoor temperature.
Cut a paper strip about 5 mm wide. Wrap it around the base of the finger without compressing the skin. The strip should be secure but should still represent a ring that can move over the knuckle. Avoid elastic thread, thick cord and soft fabric tape.
Mark the exact overlap, open the strip and measure from its starting edge to the mark. Record the result as your 指围, or finger circumference. A reading of 5.4 cm equals 54 mm and points to China GB/ISO size 54.
If the knuckle is noticeably larger than the finger base, measure both areas. A ring must pass the knuckle without pain but remain secure at the base. Professional sizing is preferable when the two measurements differ significantly.
Repeat at least three times, ideally at more than one time of day. Keep the circumference and diameter in millimetres even after choosing a listed size. Those raw figures are the best protection against ambiguous local or imported numbering.
Use a comfortable, round ring that already fits the exact finger and hand. A ring borrowed from another finger can create a misleading measurement even when it looks similar.
Lay the ring flat and measure straight across the widest internal point through the centre. Do not include the metal wall. The Chinese term for inner diameter is 内径.
Turn the ring about 90 degrees and measure again. Similar readings suggest that the ring is round. Different readings can indicate an oval, worn or damaged band, making professional measurement safer.
Select “Existing Ring Inner Diameter in MM”. An inner diameter near 17.19 mm converts to about 54 mm circumference, giving a standards-based China size of approximately 54.
The current Chinese national standard GB/T 11888-2021, Jewellery—Ring-size—Definition, measurement and designation, became effective on 1 May 2022. It aligns with the international ring-size framework and makes the internal ring measurement the key reference. In standards-based use, a size such as 52 corresponds to an internal circumference close to 52 mm.
Mainland luxury-brand websites commonly display sizes in this circumference range. For example, product selectors may show sizes from the 40s through the 70s. That does not mean every Chinese shop uses the same presentation. Domestic marketplace listings can instead show a small number followed by 号, and those seller charts are not always interchangeable.
This is why a statement such as “I need size 12” is incomplete in China. It might refer to a marketplace chart, another Asian scale or an imported brand's table. A professional order should state: finger circumference, ring inner diameter, requested sizing system and band width.
Broad wedding bands usually require more fitting attention than slim rings.
The ring must move over the knuckle and remain secure at the base.
Cold northern winters and hot, humid summers can temporarily affect finger fullness.
The same named finger can differ between dominant and non-dominant hands.
Full-eternity, tension and complex stone-set rings need precise sizing before purchase.
Rounded interiors can feel different from flat-edged rings with the same nominal size.
Open the exact product's size chart rather than using a general chart from the platform. Confirm whether the selector shows circumference-based sizes such as 52 or smaller seller-defined numbers. Review the product's band width and the model's size notes.
Send the seller your finger circumference and inner diameter in millimetres through the platform chat. Ask the seller to recommend the displayed option in writing and save that exchange with the order record.
Check the tag, certificate, invoice, material mark and physical condition before removing protective packaging. Try the ring at a normal temperature and confirm it passes the knuckle without pain.
Engraving and bespoke changes can restrict returns. Confirm the final internal circumference, finished band width and resizing allowance before authorising personalised production.
A shopper measures the intended finger three times and obtains readings of 51.8 mm, 52.1 mm and 52.0 mm. The consistent result is approximately 52 mm, so the Ring Measure in China calculator recommends China GB/ISO size 52. The shopper then checks the specific ring's width and sizing note. Because the product selector displays circumference-style numbers in the 40–70 range, size 52 is a logical starting point. The order record should still retain the 52 mm circumference and 16.55 mm approximate inner diameter.
Another shopper measures an existing ring at 17.19 mm inside diameter. That converts to approximately 54 mm circumference and a standards-based size of about 54. The product listing, however, offers choices such as 8号, 10号 and 12号 without displaying millimetres. The shopper should not guess a number by using a simple formula. The correct approach is to open the seller's exact chart or ask which option corresponds to an inner diameter near 17.19 mm. Saving the written seller recommendation helps if the delivered size differs from the stated measurement.
A customer knows that an existing ring is approximately US size 7.5, but the new seller requests circumference. The conversion chart points to about 56 mm circumference and 17.83 mm inner diameter. Instead of sending only “US 7.5,” the customer provides all three references and explains which finger and hand will wear the ring. This gives the seller enough information to reconcile the imported size with its own manufacturing chart.
A narrow sample ring fits comfortably at 55 mm circumference, but the planned wedding band is much wider. Wide rings commonly feel tighter because more of the inner surface touches the finger. The couple should try a band of similar width or request design-specific fitting rings. It may be appropriate to select a slightly larger finished size, but the adjustment should come from a physical fitting or the maker's recommendation rather than an automatic rule.
For a bespoke ring, the customer supplies 58 mm circumference, 18.46 mm inner diameter, intended finger, dominant hand, preferred fit and the planned band width. The jeweller confirms the finished internal measurement in writing before production. This is more precise than saying only “Chinese size 18,” which could be interpreted through a different numbering chart. Custom orders should also confirm whether final polishing, engraving or stone setting could affect resizing options.
These official standards, brand resources and public consumer references support the measurement and buying guidance used in this page: