Lab Grown Diamond Ring Size Guide: How to Measure Perfectly at Home
Getting the right ring size is crucial when purchasing a lab grown diamond ring online. A ring that's too tight is uncomfortable, while one that's too loose risks losing your precious stone. This comprehensive guide ensures you find your perfect fit without visiting a jeweler.
Method 1: The String or Paper Strip Method
The simplest way to measure your ring size at home:
- Cut a thin strip of paper or non-stretchy string (about 6 inches long)
- Wrap it around the base of the finger you want to size
- Mark where the paper/string overlaps with a pen
- Lay it flat and measure the length in millimeters
- Compare the measurement to a ring size chart:
| Circumference (mm) | US Size | EU Size |
|---|---|---|
| 44.2 | 3 | 44 |
| 46.1 | 3.5 | 46 |
| 47.8 | 4 | 47 |
| 49.3 | 4.5 | 49 |
| 50.6 | 5 | 50 |
| 52.0 | 5.5 | 52 |
| 53.1 | 6 | 53 |
| 54.4 | 6.5 | 54 |
| 55.7 | 7 | 55 |
| 57.0 | 7.5 | 57 |
| 58.3 | 8 | 58 |
| 59.5 | 8.5 | 59 |
| 60.8 | 9 | 60 |
| 62.1 | 9.5 | 62 |
| 63.4 | 10 | 63 |
Method 2: The Existing Ring Method
If you already own a ring that fits well on the desired finger:
- Place the ring on a flat surface
- Measure the internal diameter in millimeters using a ruler
- Compare to a diameter-based size chart:
| Diameter (mm) | US Size |
|---|---|
| 14.1 | 3 |
| 15.3 | 4.5 |
| 16.1 | 5.5 |
| 16.9 | 6.5 |
| 17.7 | 7.5 |
| 18.5 | 8.5 |
| 19.4 | 9.5 |
| 20.2 | 10.5 |
Method 3: Printable Ring Sizer
Many jewelers offer printable ring sizers that you can download and use at home. Ensure your printer is set to 100% scale — not "fit to page" — for accurate results.
Factors That Affect Ring Size
Temperature
Fingers swell in heat and shrink in cold. For the most accurate measurement, size your finger at room temperature during the middle of the day — not first thing in the morning (fingers are slimmest) or after exercise (fingers are swollen).
Band Width
Wider bands fit more snugly than thin bands. If choosing a band wider than 4mm, consider going up half a size. This is particularly relevant for eternity bands and stackable rings with substantial width.
Dominant Hand
Your dominant hand is typically slightly larger than your non-dominant hand. If you plan to wear your engagement ring on your left hand, measure your left ring finger specifically.
Knuckle Size
If your knuckle is significantly larger than the base of your finger, size between the two measurements. The ring needs to slide over the knuckle but sit comfortably at the base.
Time of Year
Finger size can vary by up to half a size between summer and winter. Consider when the ring will be worn most frequently.
Sizing Tips for Specific Ring Styles
Solitaire Engagement Rings
A solitaire ring typically has a narrow band, so standard sizing applies. Ensure the ring sits comfortably enough to slide past the knuckle with slight resistance but doesn't spin freely on the finger.
Three-Stone Rings
Three-stone rings have a wider profile at the top. While this doesn't always require sizing up, be aware that the extra weight may cause the ring to spin on slimmer fingers.
Eternity Bands
Full eternity bands cannot typically be resized because stones are set all the way around. Getting the right size on the first try is essential. Order half a size up if between sizes.
Stackable Rings
When planning a ring stack, consider that multiple rings on one finger effectively require slightly more room. Each additional ring may warrant going up a quarter size.
What If Your Size Changes?
Finger size naturally fluctuates due to weight changes, aging, and even hormonal shifts. If your ring no longer fits:
- Too tight: A jeweler can stretch the band slightly (up to half a size) or add a small section of metal
- Too loose: Options include sizing down, adding sizing beads, or using a ring guard insert
- Temporary changes: Ring adjusters (small silicone or metal inserts) can temporarily tighten a loose ring
Note that some settings, like channel settings and pavé settings, are more difficult to resize than simple prong settings.
Pro Tips for Accurate Measurement
- Measure at least three times and take the average
- Measure at different times of day
- If between sizes, round up rather than down — it's easier to add sizing beads than to stretch a ring
- For a surprise gift, borrow a ring from their jewelry box and trace the inner circle or press it into a bar of soap
- Many jewelers offer free resizing within a set period after purchase
Recommended Pieces
- 14K White Gold 2 1/6Ct Marquise And Round Three Stone Ladies
- 14K Yellow Gold 2 1/6Ct Marquise And Round Three Stone Ladies
- Ladies Solitaire Ring 3Ct Princess 14K Yellow Gold
Ready to find your perfect ring? Browse our lab grown diamond ring collection with confidence, knowing exactly what size to order.