THE DETAILS MATTER
US Ring Size Guide
The most reliable at-home approach is to measure a ring that already fits the intended finger. Measure its inside diameter in millimeters, then compare it with the chart below. If you do not have a ring, wrap a plain strip around the finger and measure the marked length.
Before you start
- Measure the exact finger and hand that will wear the ring.
- Measure near the end of the day when fingers are usually less cool.
- Keep the paper snug, not tight.
- Repeat the measurement two or three times.
- If your knuckle is wider than the finger base, check both points.
Method 1: measure a ring that already fits
- Choose a round ring that fits the intended finger.
- Place it flat on a ruler with millimeter markings.
- Measure straight across the widest inside edge. Do not include the metal band.
- Match that inside diameter to the chart.
Completion check: You should have one inside-diameter number in millimeters, such as 16.3 mm—not the outside width of the ring.
Method 2: measure the finger
- Cut a narrow strip of non-stretch paper.
- Wrap it around the base of the intended finger.
- Mark the exact overlap point without pulling the strip tight.
- Lay it flat and measure the marked length in millimeters.
- Match that circumference to the chart.
Completion check: The strip should slide over the knuckle with light resistance and should not leave a deep mark.
MoissaniteJewel US ring size chart
This is the sizing reference supplied for our current ring assortment. It is not a claim that every brand uses an identical conversion.
| US size | Inner circumference (mm) | Inner diameter (mm) |
|---|---|---|
| 4 | 47.7 | 15.2 |
| 4.5 | 48.7 | 15.5 |
| 5 | 49.9 | 15.9 |
| 5.5 | 51.2 | 16.3 |
| 6 | 52.1 | 16.6 |
| 6.5 | 54.3 | 17.3 |
| 7 | 55.6 | 17.7 |
| 7.5 | 56.6 | 18.0 |
| 8 | 57.5 | 18.3 |
| 9 | 59.7 | 19.0 |
Common measuring mistakes
- Measuring the outside diameter instead of the inside opening.
- Using string that stretches or compresses.
- Measuring cold fingers or immediately after exercise.
- Assuming the same size fits every finger.
- Choosing a tight result for a wider band.
If your measurement falls between sizes
Repeat the measurement at a different time of day. If it still falls between two available sizes, a slightly larger size is usually the safer starting point for a wider band or prominent knuckle. Contact us before ordering if the fit decision remains unclear.