A ring that's the wrong size is uncomfortable at best and unsafe to wear at worst, too loose and it can slip off, too tight and it can be difficult to remove. Unlike most sizing questions, though, ring size is genuinely easy to get right with the correct method, and just as easy to get wrong by guessing.
The short answer
The most accurate way to find your ring size is to measure a ring you already wear on the correct finger, either with a printable sizing chart or at a local jeweler. If you're buying as a surprise and can't ask directly, borrowing a ring the person wears on that finger (even briefly) for measurement is far more reliable than estimating from hand size or comparing to someone else's ring.
Measuring your own size
- Measure a ring you already own, worn on the same finger you're sizing for, since finger size varies between hands and fingers. Measure the inner diameter in millimeters, or take it to a local jeweler for an exact reading on a ring sizer.
- Measure at the right time of day. Fingers naturally swell slightly with heat and activity, so size later in the day rather than first thing in the morning for a more typical everyday fit.
- Avoid measuring right after exercise or in the cold, both temporarily shrink or swell fingers away from their normal size.
Sizing a ring as a surprise
This is the harder scenario, and where the most sizing mistakes happen. A few reliable approaches, roughly in order of accuracy:
- Borrow an existing ring worn on the correct finger, even for a few hours, and measure or bring it to a jeweler. This is the single most accurate option available without asking directly.
- Ask someone close to them (a family member or friend) who might already know their size or can help without giving away the surprise.
- Trace a ring's inner circle on paper if you can't take it anywhere, then compare the traced diameter to a printable sizing chart.
Guessing from hand size alone, or from a ring worn on a different finger, is the least reliable method and the most common source of resizing requests after the fact.
What if the size is wrong after all?
Most ring styles can be resized after purchase, typically within a size or two in either direction, so a close guess is rarely a permanent problem. Resizing works more easily on simple bands and prong or bezel settings than on full-eternity bands with diamonds set all the way around, since there's no plain metal section left to adjust. If there's real uncertainty, choosing a style with easier resizing potential is a reasonable hedge.
A few practical notes
- Wider bands tend to fit more snugly than thin bands at the same labeled size, so a wide band may need to run slightly larger than a thin one for the same comfortable fit.
- Dominant hands are sometimes very slightly larger than non-dominant hands, so always size the specific finger the ring will actually be worn on.
- Knuckles that are noticeably larger than the base of the finger can make a ring hard to get on and off even at the "correct" base measurement, worth mentioning to a jeweler if that applies to you.
Frequently asked questions
What's the most accurate way to find a ring size without asking?
Borrow an existing ring worn on the correct finger and measure its inner diameter, or bring it to a jeweler. It's meaningfully more accurate than estimating from hand size.
Can rings be resized after purchase?
Most styles, yes, typically within a size or two. Full-eternity bands with stones set all the way around are more limited, since there's no plain metal left to adjust.
Should I size up or down if I'm between sizes?
Generally size up slightly rather than down, a ring that's a touch loose is more comfortable and safer than one that's difficult to remove, and slightly loose rings are also easier to resize down than tight rings are to size up.
Does band width affect sizing?
Yes. Wider bands fit more snugly than thin bands at the same labeled size, so it's worth accounting for band width, not just finger measurement, when choosing a size.
Have questions about a specific piece?
Browse our Lab Diamond Rings collection, or reach out through our custom design service if you'd like help getting the fit right before you order.