The most accurate way is a standard ring sizer in store. At home, wrap a non-stretch thread around the base of your finger, mark where it meets, measure the length in mm and check the chart: by the common Vietnamese convention, circumference is about (size number + 40) mm. Measure three times in the evening; for bands 6 mm or wider, go up 0.5–1 size.
What is a ring size?
A ring size is a conventional number for the inside dimension of a ring. The same size can be described in two ways: the inside circumference (the inner circle, in mm) and the inside diameter (straight across the centre). They are linked by a simple formula: diameter = circumference ÷ 3.14.
Different systems name sizes differently. Vietnamese jewellers use numbered sizes (size 10, size 12); Europe uses the circumference in mm (size 52 = 52 mm); the US has its own scale (6, 7, 8…). When buying elsewhere or online, ask which system is used, and ideally give the circumference or diameter in millimetres.
Most women wear Vietnamese sizes 8–12 and most men 14–18. This is only a typical range and is no substitute for measuring.
Ring size conversion chart
The chart follows the common convention among Vietnamese jewellers: inside circumference ≈ size number + 40 mm. The US column is converted from the diameter using the standard US scale, rounded to the nearest half size. Brands may differ by 0.5–1 size, so use millimetres for important rings.
| VN size | Circumference (mm) | Diameter (mm) | US size | EU size |
|---|---|---|---|---|
| 6 | 46 | 14.6 | 3.5 | 46 |
| 7 | 47 | 15.0 | 4 | 47 |
| 8 | 48 | 15.3 | 4.5 | 48 |
| 9 | 49 | 15.6 | 5 | 49 |
| 10 | 50 | 15.9 | 5.5 | 50 |
| 11 | 51 | 16.2 | 5.5 | 51 |
| 12 | 52 | 16.6 | 6 | 52 |
| 13 | 53 | 16.9 | 6.5 | 53 |
| 14 | 54 | 17.2 | 7 | 54 |
| 15 | 55 | 17.5 | 7 | 55 |
| 16 | 56 | 17.8 | 7.5 | 56 |
| 17 | 57 | 18.1 | 8 | 57 |
| 18 | 58 | 18.5 | 8.5 | 58 |
| 19 | 59 | 18.8 | 9 | 59 |
| 20 | 60 | 19.1 | 9 | 60 |
| 21 | 61 | 19.4 | 9.5 | 61 |
| 22 | 62 | 19.7 | 10 | 62 |
| 23 | 63 | 20.1 | 10.5 | 63 |
| 24 | 64 | 20.4 | 11 | 64 |
Reference chart. Ngọc Diệp measures with a standard ring sizer in store for the most accurate result.
5 ways to measure ring size at home
1. Thread or a strip of paper
The most common method, and quite close if done carefully.
- Cut a non-stretch thread (sewing thread, dental floss) or a 5 mm strip of paper about 10 cm long.
- Wrap it around the base of the finger, snug but not tight. It must still slide over the knuckle when you pull it off.
- Mark where the two ends meet.
- Lay it flat on a ruler and read the length to the millimetre. This is the circumference.
- Check the chart: 52 mm is about size 12. If you fall between two sizes, choose the larger.
2. A ring that already fits
If you have a ring that fits the same finger, this beats the thread. Place it on a ruler and measure the inside diameter (inner edge to inner edge through the centre), excluding the band thickness. Use the diameter column. Use a ring with a similar band width: a thin band measures smaller than a wide one.
3. A printed paper sizer
Some jewellers offer a paper strip sizer. Print it at exactly 100% (turn off "fit to page") and check the 5 cm mark with a real ruler before use. Convenient, but accuracy depends on your printer.
4. Send a photo on Zalo
Place a ring that fits on squared paper or next to a ruler, photograph it straight from above in good light and send it to the shop. Staff estimate the inside diameter and suggest a size. Ngọc Diệp Gold Shop offers this on Zalo at +84 916 600 660.
5. A standard ring sizer in store (most accurate)
A ring sizer is a set of numbered metal rings. Try them until one fits: it slides over the knuckle with a little pressure and does not spin too easily at the base. For wedding and engagement rings, this is the method to use. At Ngọc Diệp Gold Shop, sizing is free with no purchase required.
Tips for getting it right first time
- Measure in the evening. Fingers are usually largest in the late afternoon and smallest early in the morning. Avoid measuring right after exercise or a hot shower.
- Mind the temperature. Fingers shrink in the cold and swell in the heat, by roughly 1 mm of circumference.
- Large knuckles. If your knuckle is bigger than the base, measure both and choose in between, enough to pass the knuckle without slipping off.
- Wide bands. Bands of about 6 mm or more cover more skin and feel tighter; go up 0.5–1 size.
- Dominant hand. Fingers on your dominant hand are often about half a size larger. Measure the exact finger on the exact hand.
- Measure three times. Use the most frequent or average result rather than a single reading.
- Special periods. During pregnancy, after childbirth or with big weight changes, fingers change; wait until they settle before ordering an important ring.
Measuring secretly for a surprise
To buy an engagement ring without them knowing, you can:
- Borrow a ring they often wear (ideally on the ring finger) and have it measured, or photograph it on a ruler.
- Press the ring into a bar of soap or modelling clay to capture the inside diameter.
- Ask a close friend or family member.
- Choose a common size and ask the shop about resizing after purchase.
Plain bands and single-stone rings can usually be resized by 1–2 sizes. Eternity rings and continuous patterns are very hard to resize, so measure carefully before ordering.
What if the ring is too tight or too loose?
Most gold rings can be sized up or down by cutting, soldering and re-polishing. Changes of 1–2 sizes rarely affect the shape. Keep in mind:
- White gold needs re-plating with rhodium after resizing so the colour matches.
- Rings with stones all around, engraving inside or rotating parts often cannot be resized, or only slightly.
- Sizing up a lot thins the band; the jeweller then adds gold and charges for it.
- At Ngọc Diệp, resizing jewellery bought in store is free, or charged at minimal cost when extra metal is needed.
Quick answers
What is a common women’s ring size?
Most women wear Vietnamese sizes 8–12 (about 48–52 mm circumference), but measure, as every finger is different.
What is a common men’s ring size?
Men usually wear Vietnamese sizes 14–18 (about 54–58 mm circumference).
I am between two sizes. Which should I choose?
Choose the larger, especially for wide bands; a slightly loose ring is easier to fix than one that will not pass the knuckle.
Is measuring with thread accurate?
Fairly, if you use non-stretch thread, wrap it snugly and measure three times; error is usually under one size. A standard ring sizer in store is still the most accurate.
Does Ngọc Diệp charge for ring sizing?
No. Visit 242 Cách Mạng Tháng 8, Trấn Biên Ward, Dong Nai City for free sizing with a standard sizer, or send a photo of your ring on Zalo at +84 916 600 660.
Can gold rings be resized?
Most plain or single-stone gold rings can be resized by 1–2 sizes; eternity rings and continuous patterns are very hard to resize.
