The Short Answer
The most reliable method is to borrow a ring your partner already wears on the correct finger and have it measured — or measure it yourself at home using a ring sizer or a simple ruler. If that is not possible, enlist a close friend or family member to help.
Borrow an Existing Ring
This is the gold standard. If your partner wears a ring on their left ring finger — or even their right ring finger, which is typically very close in size — you can slip it off temporarily and take it to a jeweller for measurement, or trace the inner circle on paper and measure the diameter yourself.
A few practical points:
- Choose a ring they wear on the correct finger. A ring from their index finger or thumb will give you a misleading size. The ring finger on the right hand is usually the closest match to the left.
- Borrow it briefly. Take the ring in the morning, get it measured, and return it before they notice. Most jewellers can size a ring in under a minute.
- Trace and measure. If you cannot take the ring out of the house, press it into a bar of soap or trace the inside circle on paper. Measure the inner diameter in millimetres and compare it to a standard ring size chart.
Enlist a Trusted Friend or Family Member
If borrowing a ring feels too risky, a close friend or sibling can be remarkably helpful. They might already know your partner's size, or they can create a natural opportunity to find out — a casual trip to a jewellery shop, trying on costume rings, or even gifting a fashion ring as a birthday present to establish the size.
The key is choosing someone who can keep the secret. One reliable confidant is better than a group effort where someone might let it slip.
Use a Ring Sizer at Home
Printable ring sizers and plastic ring gauge sets are widely available. You can order a ring gauge set online for a few euros and leave it somewhere accessible. If your partner is a heavy sleeper, some people have even gently measured their finger with a strip of paper while they slept — though this requires a steady hand and a sound sleeper.
A strip of paper or string wrapped around the finger and measured against a millimetre ruler gives you the circumference, which converts directly to a ring size. Just ensure you measure at room temperature — fingers swell in heat and shrink in cold.
Ask Indirectly
Sometimes the most effective approach is the most straightforward one, just lightly disguised. A few tactics that work:
- "I need help buying a ring for my mother/sister." Ask your partner to try on a ring "so I can see what size looks right" — then note their size.
- Window shopping. Browse a jewellery shop together for another occasion and casually suggest they try something on. Pay attention to which size fits.
- The ring quiz. If your partner has ever filled out one of those online ring style quizzes, they may have entered their size. Check their browser history or ask them to do one together "for fun."
What If You Still Cannot Find Out?
If all else fails, do not guess blindly. An average women's ring size in Europe falls between size 52 and 56 (EU sizing), which corresponds to roughly 16.5–17.8 mm inner diameter. Size 54 is a common middle ground. For men's rings, the average tends to fall between 60 and 66.
However, averages are just that — averages. If you are working with a jeweller who manufactures to order, as Arete does, you can discuss sizing during the design process. Our team can advise on the best approach for your situation, and because the ring is made specifically for you, the size is built in from the start rather than adjusted after the fact.
The Arete Diamond Approach
Because every Arete ring is manufactured to order, sizing is part of the design conversation — not an afterthought. When you begin working with our team, we will help you determine the correct size before production begins. If you are unsure, we can guide you through measurement options and confirm the fit before the ring is made.
Getting the size right the first time matters. A ring that fits perfectly from the moment it goes on the finger is part of the experience — and it is one less thing to worry about on the day that matters most.
Cross-References
- Ring Size Guide — comprehensive sizing charts and measurement instructions
- Engagement Ring Center Diamond — how the centre stone anchors the design
- Resizing & Repairs — when resizing is and is not possible