To find your ring size, measure around your finger in millimeters: in France, the ring size is simply that circumference (a 54 mm measurement means a size 54, which is about a US size 7). All you need is a piece of string, a ruler and two minutes, or a ring you already wear. Here are the reliable methods, our conversion chart and our tips to get it right, even when you are buying a ring as a gift. And if you are looking for a ring to engrave, our guide to personalized jewelry for her and for him is full of ideas.
Ring sizes: how do they work?
A French ring size is the inner circumference of the band, in millimeters. A size 52 ring therefore measures 52 mm around the inside. To get the inner diameter, divide that circumference by 3.14: a size 52 is about 16.6 mm in diameter.
For women, the most common sizes fall between 50 and 56 (roughly US 5 to 7.5). At L'Or Didon, our fixed-size rings come in S (51/52), M (54/55), L (57/58) and, for some designs, XL (59/60). Many others are adjustable.
Our rings in fixed sizes S, M and L
 Émeraude a touch of green among the white stones |
 Sparkling eternity band set all the way around, gold-tone or silver-tone |
 Sandra a sculpted oval, gold-tone or silver-tone |
Double band rings: two rings in one
Two bands joined into a single piece: it looks like two stacked rings, with no need to match them. They come in S, M and L. Because they cover more of the finger than a thin band, go up a size if you are between two.
 Double band |
 Plain double band |
 Two-tone double band |
 Couronne |
How to measure your ring size at home
Method 1: a piece of string or a strip of paper
- Cut a thin strip of paper (or use a piece of non-stretch string).
- Wrap it around the base of the finger you have in mind, without pulling tight.
- Mark with a pen the point where the strip overlaps.
- Lay it flat on a ruler and read the length in millimeters: that is your size.
Then check that the strip slides over your middle knuckle: the knuckle decides whether the ring will go on and come off. If your knuckle is wide, use the measurement taken over the knuckle rather than at the base.
Method 2: with a ring you already wear
Take a ring that fits you well, worn on the same finger. Measure its inner diameter with a ruler, from one inside edge to the other, without counting the metal. Then check the chart below: an inner diameter of 17.2 mm, for example, is a size 54 (US 7).
Method 3: the ring sizer
A ring sizer is the set of reference rings that jewelers use. It is the most accurate method. Printable ring sizers also exist, but always check the scale with a ruler: a printer that shrinks the page by a few percent will throw off the size.
Ring size chart: finger circumference and diameter
| Finger circumference (mm) | Inner diameter (mm) | French size | L'Or Didon size |
|---|---|---|---|
| 48 | 15.3 | 48 | adjustable |
| 49 | 15.6 | 49 | adjustable |
| 50 | 15.9 | 50 | adjustable or S |
| 51 | 16.2 | 51 | S |
| 52 | 16.6 | 52 | S |
| 53 | 16.9 | 53 | S or M |
| 54 | 17.2 | 54 | M |
| 55 | 17.5 | 55 | M |
| 56 | 17.8 | 56 | M or L |
| 57 | 18.1 | 57 | L |
| 58 | 18.5 | 58 | L |
| 59 | 18.8 | 59 | XL (depending on the design) |
| 60 | 19.1 | 60 | XL (depending on the design) |
| 61 | 19.4 | 61 | adjustable |
| 62 | 19.7 | 62 | adjustable |
Ordering from outside France? On our product pages, S corresponds to US size 6, M to US 7, L to US 8 and XL to US 9.
Now that you know your size, discover all our gold-tone and silver-tone rings, in fixed sizes or adjustable.
Mistakes to avoid when measuring your ring size
- Measuring first thing in the morning or in the cold. Fingers are slimmer when you wake up and swell during the day and in the heat. Measure at the end of the day, at a normal temperature, and take two or three measurements.
- Forgetting which hand. Your writing hand is often slightly larger: a ring that fits your left hand may feel tight on the right.
- Forgetting the width of the ring. A wide ring, like our dome ring or the Couronne double ring, covers more of the finger and feels tighter than a thin band. Go up half a size, or even a full size.
- Using stretchy string. It stretches and gives you a size that is too small.
Between two sizes? Choose the larger one: a slightly loose ring can still be worn, a ring that is too small will not slide over the knuckle.
Adjustable rings: one size for every finger
On the index finger, the ring finger, the thumb or stacked on the middle finger: an adjustable ring goes wherever it suits you, depending on your mood. Its slightly open band adjusts with a gentle squeeze and fits every finger. And if you are giving it without knowing her size, it is the risk-free choice: it will always fit.
Dainty and delicate or wide and bold, here are our favorites:
 Christelle generous, luminous white mother-of-pearl |
 Philippine reversible: mother-of-pearl or pink stone, as the day calls for |
 Juliette warm, intense tiger's eye |
 Calista fine and sparkling, perfect for stacking |
 Lia a delicate double bow |
 Twisted a twisted band that catches the light |
Giving a ring without knowing her size
It is a classic dilemma when you want to surprise someone. Three simple solutions:
- Discreetly borrow a ring she wears on the right finger, and measure its inner diameter as explained above.
- Ask a friend or relative who knows her size, or who wears the same one.
- Choose an adjustable ring: it is the risk-free option. It fits every finger and looks just as good on the index finger as on the pinky.
For an even more personal gift, the Signature ring, also adjustable, combines an engraved medallion and a natural stone. For more ideas, read our article on jewelry gifts for mom.
Ring too big or too small: what can you do?
You have 14 days after delivery to return a ring that does not fit (return shipping costs are at your expense). Exchanges are free in our boutique in Le Marais, Paris. Please note that an engraved ring is made especially for you: it cannot be returned, so double-check your size before ordering a personalized signet ring.
The easiest way is still to come and try them on at our boutique in Le Marais, Paris (3 rue Madame de Sévigné, Saint-Paul metro), open every day from 11 am to 8 pm. You can also browse our ring collection online.
Ring size FAQ
What is the most common ring size for women?
Most women wear a French size between 50 and 56 (about US 5 to 7.5), with size 54 (US 7) being very common on the ring finger. That is why size M (54/55) is often a good starting point if you are unsure.
How can I measure my ring size without string?
Measure the inner diameter of a ring that fits you with a ruler, then find your size in the chart. A strip cut from a sheet of paper also works very well.
Does adjusting a ring damage it?
No, as long as you open or close it gently, just once, to find your size. Avoid adjusting it every day: that is what tires the metal.
What is the difference between French and US ring sizes?
The French size gives the finger circumference in millimeters, while US sizes follow a simple number scale. On our product pages, S corresponds to US size 6, M to US 7, L to US 8 and XL to US 9.
Article updated on October 20, 2026
