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.
Contents
- Ring sizes: how do they work?
- How to measure your ring size at home
- Ring size chart: finger circumference and diameter
- French, US and UK ring sizes: the conversions
- Mistakes to avoid when measuring your ring size
- Which ring size for which finger?
- Adjustable rings: one size for every finger
- How to wear and care for your rings
- Giving a ring without knowing her size
- Ring too big or too small: what can you do?
- Ring size FAQ
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.
This is not a jeweler's invention: it is the system of the international standard ISO 8653 on ring sizes, which defines a ring size by the inner circumference of the band in millimeters. That is why a size 54 is the same in France, Belgium, Switzerland or Germany.
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).
Tip: if the ring is not perfectly round, measure the diameter in both directions and take the average. And pick a thin, plain band if you can: it is easier to measure than a wide or stone-set ring.
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 |
Now that you know your size, discover all our gold-tone and silver-tone rings, in fixed sizes or adjustable.
French, US and UK ring sizes: the conversions
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.
Each country has kept its own system. The United States and Canada use numbers (from about 3 to 13). The United Kingdom and Australia use letters: size C equals a 40 mm circumference, and each letter adds about 1.25 mm, as explained in the Wikipedia article on ring size. France, Belgium and Switzerland use the finger circumference in millimeters.
| L'Or Didon size | French size (circumference in mm) | United States and Canada | United Kingdom and Australia |
|---|---|---|---|
| S | 51 to 52 | 6 | L to M |
| M | 54 to 55 | 7 | N to O |
| L | 57 to 58 | 8 | P to Q |
| XL | 59 to 60 | 9 | R to S |
These conversions are rounded, because the scales never line up exactly. The safest option is to measure your finger in millimeters and compare it with the French column. That is also what we recommend to the many American and Canadian customers who visit our boutique in Le Marais.
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.
- Pulling the paper strip too tight. It should slide around your finger without marking the skin. A measurement that is too tight gives you a ring that will not pass over the knuckle.
- Printing a ring sizer without checking the scale. Always check the 1 or 2 cm reference mark on the sheet with a ruler.
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.
Which ring size for which finger?
Your fingers are not all the same size. A measurement taken on the ring finger will not work for the index finger or the thumb. Here are the guidelines to keep in mind, for a woman's hand:
| Finger | Compared with the ring finger | Our advice |
|---|---|---|
| Pinky | Often 2 to 4 sizes smaller | A dainty or adjustable ring, gently closed |
| Ring finger | The reference | The size used for wedding bands and everyday rings |
| Middle finger | Often 1 to 2 sizes larger | The ideal finger for a bold statement ring |
| Index finger | Close to the middle finger | Perfect for a stone ring or a signet ring |
| Thumb | Noticeably wider | Measure it separately, or choose an adjustable ring |
These differences vary from person to person: always measure the exact finger where you will wear the ring. For a thumb ring or a pinky ring, an adjustable ring is still the simplest solution.
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 |
To avoid tiring the metal, adjust your ring only once, gently, holding it with both hands: open or close the band with small presses, never with a sharp twist.
How to wear and care for your rings
Once you have found the right size, the fun begins. At L'Or Didon, we love hands that dare: a statement piece on the middle finger, several thin bands that echo each other, a mix of gold-tone and silver-tone.
- The rule of three. Three rings on one hand are enough for a curated look without overload. Keep the other hand lighter.
- One statement piece, a few thin bands. Pair a wide or hammered ring with one or two thin bands on the neighboring fingers.
- Stacking on the same finger. Two thin bands worn together should be the same size. For a midi ring, worn above the knuckle, go 2 to 3 sizes smaller, or choose an adjustable ring.
- Dare to mix metals. A two-tone ring ties your gold-tone and silver-tone jewelry together.
 Eternity set all around, also in XL |
 Marcelle the hammered statement piece |
 Multi-band the stacked look in a single ring |
 Nacréa a touch of pearls |
Care tips: our rings are made of surgical stainless steel with an 18k fine gold finish, so they hold up well to everyday wear. A few simple habits keep them shining longer:
- Take your rings off for sports, housework and chemicals (hand sanitizer, bleach).
- Apply hand cream before putting on your rings, and let it soak in.
- Wipe them with a soft, dry cloth and store them separately to avoid scratches.
- For mother-of-pearl or natural stone rings, avoid water and perfume.
You will find all our detailed advice in our article on stainless steel jewelry and how to care for it, and on our jewellery care page. Our fine fashion jewelry comes with a 1-year warranty against manufacturing defects.
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.
No ring at hand to measure? Place one of hers on a sheet of paper and trace its inner circle with a fine pencil: you will only need to measure the circle's diameter. And if you are really unsure, a necklace or a bracelet is a gift with no size at all.
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, or our selection of 10 Christmas jewelry gift ideas.
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). This is the legal withdrawal period for distance purchases in France, detailed by the French Ministry of the Economy on its page on the right of withdrawal for distance selling (in French). 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.
In the meantime, a ring that is slightly too big can be worn on the neighboring finger, which is often a little wider: the middle finger instead of the ring finger, for example. A ring that is a little snug may slide on more easily in the evening, when fingers are warmer, but never force it over the knuckle.
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.
Can my finger size change?
Yes. It varies during the day, with heat, cold and physical effort, and also over the years. If a ring you love starts to feel tight, measure again at the end of the day before ordering a new one.
How do I find a man's ring size?
The same methods work: a paper strip, an existing ring or a ring sizer. Men's sizes are simply larger, often above 60 (around US 9 and up). For a gift, an adjustable ring like the Signature ring avoids any mistake.
Article updated on October 21, 2026.
