Table of Contents
The 3-Step Quick Measurement
No matter how you measure at home, remember the golden rule: The best time to measure is in the late afternoon/evening when your fingers are warm.
1. What to Measure?
Choose the data point that is easiest for you to measure accurately:
- Inner Diameter (mm): Use this if you have an existing ring that fits well.
- Circumference (mm): Use this if you are measuring your finger directly with string or paper.
2. How to Measure?
| Measurement Type | Method | Key Point |
| Existing Ring (Inner Diameter) | Use a ruler to measure the widest distance inside the ring band. | ⚠️ Do not include the thickness of the metal band itself. |
| Finger (Circumference) | Wrap string or paper around the thickest part of your finger (usually the knuckle). | ⚠️ Ensure a comfortable, snug fit—not too tight, not too loose. |
3. Use the Chart (See Below)
Match your measured $mm$ value directly to the chart to find your corresponding size number.
| Scenario | Recommendation |
| Between two sizes? | Always choose the larger size. It’s better for a ring to be slightly loose than too tight. |
| Wide Band (＞4mm)? | Wide rings feel tighter. Go up a half or full size. |
| Knuckle is wider than the base? | The size must be large enough to pass the knuckle. Choose the slightly larger measurement. |
| Left vs. Right Hand? | Your dominant hand is usually larger. Measure the exact hand you plan to wear the ring on. |
Complete International Ring Size Conversion Chart
Note: Circumference is the most common international standard and is widely used by global brands.
| China/Japan Size (No.) | US Size (No.) | UK/Aus Size | European Size | Circumference (mm) | Diameter (mm) |
| 5 | 3 | F | 44 | 44.2 | 14.1 |
| 6 | 3 1/2 | G | 45 | 45.5 | 14.5 |
| 7 | 4 | H | 46 | 46.5 | 14.8 |
| 8 | 4 1/2 | I | 48 | 48.0 | 15.3 |
| 9 | 5 | J | 49 | 49.3 | 15.7 |
| 10 | 5 1/2 | K | 50 | 50.6 | 16.1 |
| 11 | 6 | L | 51 | 51.9 | 16.5 |
| 12 | 6 1/2 | M | 53 | 53.1 | 16.9 |
| 13 | 7 | N | 54 | 54.4 | 17.3 |
| 14 | 7 1/2 | O | 55 | 55.7 | 17.7 |
| 15 | 8 | P | 56 | 56.9 | 18.1 |
| 16 | 8 1/2 | Q | 58 | 58.2 | 18.5 |
| 17 | 9 | R | 59 | 59.5 | 18.9 |
| 18 | 9 1/2 | S | 60 | 60.8 | 19.3 |
| 19 | 10 | T | 61 | 62.1 | 19.8 |
| 20 | 10 1/2 | U | 63 | 63.3 | 20.2 |
| 21 | 11 | V | 64 | 64.6 | 20.6 |
| 22 | 11 1/2 | W | 65 | 65.9 | 21.0 |
| 23 | 12 | X | 67 | 67.2 | 21.4 |
| 24 | 12 1/2 | Y | 68 | 68.4 | 21.8 |