DESIGN YOUR OWN ENGAGEMENT RING
Ring size is the single most common reason a ring goes back to the workshop. It is also the easiest thing to get right, provided you avoid a handful of predictable mistakes.
Before you measure: four rules
These affect your result more than the method you choose.
- Measure at the end of the day. Fingers are at their largest in the evening. Measure first thing in the morning and you will size too small.
- Be warm. Cold fingers shrink noticeably. If you have just come in from outside, wait.
- Measure the correct hand. Your dominant hand is usually half a size larger.
- Measure three times on different days. Fingers fluctuate with heat, salt, exercise and hormones. Take the most consistent reading, not the first.
Method 1: Measure a ring you already own
The most accurate approach, if you have a ring that fits the right finger.
- Take a ring that fits comfortably — snug, but comes off over the knuckle without a fight.
- Measure the inside diameter across the widest point, in millimetres.
- Match it to the chart below.
Measure the inside edge to inside edge, not the outside. On a wide band, measure at the centre of the width.
Method 2: String or paper strip
Use this if you have no reference ring.
- Cut a strip of paper about 5mm wide, or use a piece of non-stretchy string.
- Wrap it around the base of the finger. Snug, not tight — it should sit as a ring would.
- Check it passes over your knuckle at that tension. This step is the one people skip, and it is why rings end up stuck.
- Mark where the strip overlaps and measure the length in millimetres.
- That length is your circumference. Match it below.
Do not use thread or elastic — both stretch and will give you a size too small.
Method 3: Printable sizer
Printable ring sizers work, but only if the print scale is exactly 100%. Print it, then measure the printed ruler against a real one before trusting it. A page scaled to "fit to page" will be wrong by a size or more.
Size chart
| US size | Inside diameter (mm) | Circumference (mm) |
|---|---|---|
| 4 | 14.9 | 46.8 |
| 4.5 | 15.3 | 48.0 |
| 5 | 15.7 | 49.3 |
| 5.5 | 16.1 | 50.6 |
| 6 | 16.5 | 51.9 |
| 6.5 | 16.9 | 53.1 |
| 7 | 17.3 | 54.4 |
| 7.5 | 17.7 | 55.7 |
| 8 | 18.1 | 57.0 |
| 8.5 | 18.5 | 58.3 |
| 9 | 18.9 | 59.5 |
| 9.5 | 19.4 | 60.8 |
| 10 | 19.8 | 62.1 |
| 10.5 | 20.2 | 63.4 |
| 11 | 20.6 | 64.6 |
| 11.5 | 21.0 | 65.9 |
| 12 | 21.4 | 67.2 |
| 12.5 | 21.8 | 68.5 |
| 13 | 22.2 | 69.7 |
Between two sizes? Go up, not down. A slightly loose ring can be sized down easily; a ring that will not pass the knuckle cannot be worn at all.
Two things that change the size you need
Band width
A wide band covers more of the finger and fits more tightly than a narrow one at the same nominal size. For a band 6mm or wider, go up a quarter to a half size. This catches a lot of people who order a slim engagement ring and a wide wedding band in the same size.
Large knuckles
If your knuckle is significantly wider than the base of your finger, the ring has to clear the knuckle but will then spin at the base. Size for the knuckle, and ask about sizing beads — two small beads added inside the band that hold it steady without preventing it going on.
Measuring a partner's finger without them knowing
If it is a surprise, these work:
- Borrow a ring. The most reliable route. Take one they wear on the correct finger — the ring finger of the correct hand — and measure the inside diameter, or press it into a bar of soap to leave an impression.
- Ask someone who would know. A sibling, best friend or parent can often ask casually without raising suspicion.
- Compare hands. If your hands are similar in size, try their ring on your own finger and mark where it stops.
- Size up and resize later. If you genuinely cannot find out, order a size 6.5 (the most common size for women) or 9.5 (for men), propose, and have it sized properly afterwards. Almost nobody minds.
What can and cannot be resized
Most plain and solitaire bands resize easily, usually within two sizes in either direction.
Harder or impossible:
- Full eternity bands — stones go all the way round, so there is no plain metal to cut. Generally cannot be resized.
- Pavé shanks — resizing risks loosening the stones. Limited movement only.
- Tension settings — the fit depends on the metal's spring pressure. Resizing alters it.
If you are choosing any of these, measure carefully first. It is worth the extra day.
Still unsure? Send us a message — we would rather spend ten minutes getting it right than have you post a ring back.
