Choosing the right ring size is one of the most important steps when buying an engagement ring, a wedding band or any piece you plan to wear every day. Too tight and it is uncomfortable; too loose and it can slip off. In this guide you will learn how to measure your ring size at home, how to read the US, UK and European ring size charts, and a few practical tips that make all the difference.
How to measure your ring size at home
You only need to know one number: the circumference of your finger in millimetres (or the inner diameter of a ring that already fits). Here are the two easiest methods.
Method 1: With a piece of string or paper
- Cut a thin strip of paper or a piece of string, about 10 cm long.
- Wrap it around the base of the finger where the ring will go.
- Mark the point where the ends meet.
- Lay it flat against a ruler and read the length in millimetres. That is your finger circumference.
- Look up that number in the chart below.
Method 2: With a ring that already fits
- Choose a ring that fits well on the same finger.
- Measure the inside diameter in millimetres, from one inner edge to the other.
- Find the closest match in the chart below.
Ring size chart: US, UK and EU conversion
Each country measures rings differently. The US uses numbers (with half sizes), the UK uses letters, and Europe uses the circumference of the ring in millimetres. Use this ring size conversion chart to compare them:
| US size | UK size | EU size (approx.) | Inner diameter | Circumference |
|---|---|---|---|---|
| 5 | J½ | 49 | 15.7 mm | 49.3 mm |
| 5½ | K½ | 50 | 16.1 mm | 50.6 mm |
| 6 | L½ | 52 | 16.5 mm | 51.8 mm |
| 6½ | M½ | 53 | 16.9 mm | 53.1 mm |
| 7 | N½ | 54 | 17.3 mm | 54.4 mm |
| 7½ | O½ | 56 | 17.7 mm | 55.7 mm |
| 8 | P½ | 57 | 18.1 mm | 57.0 mm |
| 9 | R½ | 59–60 | 18.9 mm | 59.5 mm |
| 10 | T½ | 62 | 19.8 mm | 62.1 mm |
Sizes can vary slightly between brands and countries, so treat this chart as a guide and confirm your size before ordering.
7 tips to get your ring size right
- Measure at the end of the day. Fingers are slightly larger in the evening than first thing in the morning.
- Avoid measuring when it is very cold or very hot. Cold shrinks your fingers and heat makes them swell. Warm room temperature is ideal.
- Measure two or three times on different days and take the most common result.
- Consider your knuckle. If your knuckle is bigger than the base of your finger, the ring has to slide over it. Pick a size that passes the knuckle with a little resistance and sits comfortably at the base.
- Wide bands need a bigger size. A band wider than about 6 mm fits tighter than a thin one, so many people go up half a size.
- Your dominant hand is usually slightly larger. Measure the finger that will actually wear the ring.
- If it is a surprise, borrow a ring. Take a ring she already wears on that finger and measure the inside diameter, or trace its inside on paper. If in doubt, ask a close friend or family member.
Can a ring be resized?
In most cases, a classic gold ring can be resized by one or two sizes. But there is an important exception: rings with diamonds all the way around the band, such as a full eternity ring, are very difficult or impossible to resize without damaging the stones. A half eternity ring has limited room for resizing. For these designs, getting the size right from the start matters even more.
My advice: if you are between two sizes, choose the larger one for a wide band or an eternity ring, and the smaller one for a thin solitaire. And if you are not sure, send us your measurement and we will help you decide before you order.
Find your perfect ring at Antonio Amberes
Once you know your size, browse our solitaire engagement rings, halo rings, pavé rings and eternity bands, with natural or lab-grown diamonds. Not sure which diamond to pick? Read our guide to lab-grown vs natural diamonds, or see what to look for when buying diamonds in Antwerp.
Ring size FAQ
What is the most common ring size for women?
In the US, sizes 6 to 7 are the most common, which is roughly EU 52–54 and UK L½–N½. It varies a lot from person to person.
Is the European ring size the same as the circumference?
Roughly, yes. European sizes follow the inner circumference of the ring in millimetres, so a size 54 has an inner circumference of about 54 mm.
Should I size up for a wide band?
Often yes. Wider bands feel tighter, so going up about half a size is common for bands wider than 6 mm.
Can my ring size change over time?
Yes. Weight changes, temperature, pregnancy or simply age can change your size slightly. If your ring feels tight or loose, re-measure.
How do I find my ring size for a surprise proposal?
Borrow a ring she already wears on that finger and measure its inside diameter, or ask someone close to her. Choosing a style that can be resized gives you extra peace of mind.
Need help finding your size? Message me on WhatsApp and we will work it out together.