Finding the right ring size shouldn't be guesswork. Whether you're treating yourself or buying for someone you love, getting the fit right is the difference between a ring that's worn every day and one that stays in the box. At CINCO, we want every piece to feel like it was made for you — because it was.
Here's everything you need to know about ring sizing.
Why Ring Size Matters
A ring that's too tight is uncomfortable and difficult to remove. A ring that's too loose risks slipping off — and losing a piece you love. The right size sits snugly on the finger, slides over the knuckle with gentle resistance, and stays in place throughout the day.
The good news: measuring your ring size at home is easier than you think.
How to Measure Your Ring Size at Home
Method 1: String or Paper Strip
This is the most accurate at-home method.
- Cut a thin strip of paper or use a piece of string.
- Wrap it snugly around the base of the finger you want to measure — not too tight, not too loose.
- Mark where the paper or string overlaps.
- Measure the length in millimetres.
- This measurement is your finger's circumference — use the chart below to find your size.
CINCO tip: Measure at the end of the day, when fingers are slightly larger. Avoid measuring when hands are cold.
Method 2: Use an Existing Ring
If you already have a ring that fits well, you can use it to find your size.
- Place the ring on a ruler.
- Measure the internal diameter in millimetres (across the inside of the ring).
- Use the chart below to match the diameter to your size.
International Ring Size Conversion Chart
Ring sizes vary by country. Here's how the most common systems compare:
| Diameter (mm) | Circ. (mm) | EU | UK | US / Can | France / Russia |
|---|---|---|---|---|---|
| 14.9 | 46.8 | 47 | H | 4 | 47 |
| 15.3 | 48.0 | 48 | H½ | 4½ | 48 |
| 15.7 | 49.3 | 49 | I½ | 5 | 49 |
| 16.1 | 50.6 | 51 | J½ | 5½ | 51 |
| 16.5 | 51.9 | 52 | K½ | 6 | 52 |
| 16.9 | 53.1 | 53 | L½ | 6½ | 53 |
| 17.3 | 54.4 | 54 | M½ | 7 | 54 |
| 17.7 | 55.7 | 56 | N½ | 7½ | 56 |
| 18.1 | 57.0 | 57 | O½ | 8 | 57 |
| 18.5 | 58.3 | 58 | P½ | 8½ | 58 |
| 19.0 | 59.5 | 60 | Q½ | 9 | 60 |
| 19.4 | 60.8 | 61 | R½ | 9½ | 61 |
In Portugal and most of Europe, ring sizes follow the circumference in millimetres — so a size 52 means a finger circumference of approximately 52mm. The system CINCO uses is diameter (mm).
Tips for Getting the Right Fit
- Fingers change size throughout the day — they're slightly larger in the evening and in warm weather. Measure at the end of the day for the most accurate result.
- Dominant hand fingers are usually slightly larger — if you're buying for the right hand, measure the right hand.
- Knuckle size matters — if your knuckle is significantly wider than the base of your finger, size up and use a ring adjuster if needed.
- Wide bands fit tighter — if you're buying a wide band (over 6mm), consider going half a size up for comfort.
- When in doubt, size up — it's easier to resize a ring that's slightly too large than one that's too small.
Buying a Ring as a Gift: How to Find Their Size
Buying a ring as a surprise is one of the most romantic gestures — and one of the trickiest. Here are a few ways to find the right size without giving it away:
- Borrow a ring they already wear on the same finger and measure the internal diameter.
- Ask a friend or family member who might already know.
- Check their jewelry box — a ring that fits the finger you're buying for is your best reference.
- Use the hand as a guide: if their hands are similar in size to yours, your size is a good starting point.
- Choose a resizable style — many CINCO rings can be resized. Contact us and we'll advise on which styles offer this option.
Still unsure? Our team is always happy to help — reach out before you order and we'll guide you to the right size.
CINCO Ring Collections
Once you know your size, explore our full ring collection — from delicate silver 925 rings to timeless 18ct solid gold rings. Each piece is handmade in Portugal and available in a range of sizes.
Looking for a gift? Our Rings Under 100€ collection is a beautiful place to start.
Related Guides
- Clasp Types: The Complete Guide to Jewelry Closures
- Chain Types: The Complete Guide to Jewelry Chains
- Earring Backs Explained: The Complete Guide to Earring Closures
Still have questions about sizing? Contact our team — we're here to help you find the perfect fit.