Diamond Ring Size Guide
Diamond specialises in fine jewellery, particularly engagement rings and wedding bands crafted to celebrate life's most precious moments. A perfectly fitted ring is essential—it should feel secure without restriction, sit comfortably at the base of your finger, and slide smoothly over your knuckle. This guide helps you find your exact ring size across UK, US, and EU sizing systems, ensuring your Diamond ring fits as beautifully as it looks.
How to Measure Your Ring Size
- Gather your materials: You will need a piece of string or a thin strip of paper (approximately 6mm wide), a ruler or tape measure, and a pen.
- Wrap around your finger: Gently wrap the string or paper around the base of your ring finger (or the fourth finger on your left hand). Do not wrap too tightly—the ring should slide over your knuckle to be removed, so ensure the measurement allows for that movement.
- Mark the overlap: Mark both pieces of the string or paper where they overlap, creating a clear reference point.
- Measure the distance: Lay the marked string or paper flat on a ruler and measure the distance in millimetres between the two marked points. This is your finger circumference.
- Match to the chart: Use your measurement (in millimetres) to locate your size in the ring size conversion table below. If you fall between sizes, always round up—it is easier to resize a ring down than up.
- Consider the time of day: Fingers are smallest in the morning and slightly fuller in the afternoon and evening. Measure at the end of the day for the most accurate fit during normal wear.
Ring Size Conversion Chart: UK, US, and EU
| UK Size | US Size | EU Size | Circumference (mm) | Diameter (mm) |
|---|---|---|---|---|
| C | 1.5 | 40.5 | 40.4 | 12.77 |
| D | 2 | 41.5 | 41.7 | 13.29 |
| E | 2.5 | 42.75 | 42.9 | 13.60 |
| F | 3 | 44.5 | 44.2 | 14.02 |
| G | 3.5 | 45.5 | 45.5 | 14.43 |
| H | 4 | 46.5 | 46.8 | 14.85 |
| I | 4.5 | 47.75 | 48.0 | 15.26 |
| J | 4.75 | 49.5 | 48.7 | 15.47 |
| K | 5.25 | 50.25 | 50.0 | 15.88 |
| L | 5.75 | 51.5 | 51.2 | 16.30 |
| M | 6 | 52.5 | 52.5 | 16.50 |
| N | 6.25 | 54 | 53.8 | 16.71 |
| O | 7.25 | 55.25 | 55.1 | 17.54 |
| P | 7.75 | 56.25 | 56.3 | 17.95 |
| Q | 8.25 | 57.5 | 57.6 | 18.37 |
| R | 8.75 | 58.5 | 58.9 | 18.78 |
| S | 9.25 | 60.25 | 60.2 | 19.20 |
| T | 9.75 | 61.25 | 61.4 | 19.61 |
| U | 10.25 | 62.5 | 62.7 | 20.03 |
| V | 10.75 | 63.73 | 64.0 | 20.44 |
| W | 11.25 | 65.25 | 65.3 | 20.85 |
| X | 11.75 | 66.25 | 66.6 | 21.27 |
| Y | 12.25 | 67.5 | 67.8 | 21.68 |
| Z | 12.75 | 68.75 | 68.5 | 21.89 |
Note: All size comparisons are accurate to within approximately 1/4 of a finger size. EU circumference measurements are the most precise reference point if you have access to a tailor's tape.
Product-Specific Guidance
Engagement Rings
Diamond engagement rings are crafted to centre a precious stone and celebrate the significance of your commitment. When selecting your size, ensure the ring sits snugly at the base of your finger without rotating. The shank width can affect perceived fit—wider bands (6mm or more) may feel tighter than standard bands at the same stated size. If you are ordering a wide-band or halo-set design, consider sizing up by half a size for comfort.
Solitaire Settings
Classic solitaire rings with a standard 2mm band typically fit true to size. However, if your solitaire features a wider shank or delicate setting, sizing up half a size is recommended to ensure smooth removal and comfortable daily wear.
Bridal Sets
Bridal sets consist of an engagement ring paired with a matching wedding band. When stacking both rings together, the combined width means the pair will feel tighter than a single ring. Order your engagement ring true to size and your wedding band half a size up, or consult the product notes for band-specific guidance. This ensures both rings sit comfortably together and allow for easy removal.
Wedding Bands
Wedding bands are worn alongside engagement rings or as standalone pieces. For comfort and proper fit, measure as described above. If you are stacking your band with an engagement ring, size up by half a size to accommodate the combined width.
Statement & Fashion Rings
Bold, contemporary designs may run slightly larger due to their wider construction or distinctive shank shape. Always refer to the product size guide on your chosen piece, as fit can vary by design. When in doubt, choose the larger size—resizing down is far simpler than resizing up.
Sizing Tips
- Measure at the end of the day: Your fingers are smallest in the morning and swell slightly throughout the day. For the most accurate fit during normal wear, measure in the late afternoon or evening.
- Account for temperature and hydration: Cold hands cause fingers to contract, while warmth and activity cause them to swell. Measure when your body temperature and hydration are typical for how you normally wear your ring.
- If between two sizes, always size up: A ring that is slightly loose is far easier to resize down than one that is too tight. Resizing a ring down may affect the setting, particularly for solitaires and complex designs.
- Consider your lifestyle: If you wear your ring daily, ensure it is comfortable enough that you will not want to remove it frequently. A snug fit is ideal for everyday wear; a slightly looser fit may be acceptable for occasional wear.
- Test the fit over your knuckle: Your ring must slide smoothly over your knuckle to be removed. Measure at the base of your finger where the ring sits during wear, not at the knuckle.
- Use EU circumference as your primary reference: If you have access to a tailor's tape, measure your circumference directly in millimetres and match it to the EU circumference column in the chart. This is the most precise measurement available.
- Leverage Diamond's resizing service: Many Diamond rings can be resized free of charge or at minimal cost. If you are unsure of your size or fall between two sizes, order the larger size and contact Diamond's expert jewellers at 1-800-557-7095 to discuss resizing options.