"Is 2 carats big?" is impossible to answer in carats — carat is a weight (1 carat = 0.2 grams), and what your eye actually reads is millimeters across the top of the stone. This chart converts the two, for the shapes we sell, so you can picture a stone's real size before you order.
Round moissanite: carat to millimeter
| Carat weight | Diameter (mm) | Rough visual reference |
|---|---|---|
| 0.25 ct | 4.0 mm | Delicate accent size — classic small stud territory |
| 0.50 ct | 5.0 mm | Noticeable but understated solitaire |
| 0.75 ct | 5.8 mm | Sweet spot for a low-key everyday ring |
| 1.00 ct | 6.5 mm | The benchmark — reads clearly as "one carat" |
| 1.50 ct | 7.5 mm | Clearly larger; strong presence on the hand |
| 2.00 ct | 8.0 mm | Bold — most people guess it weighs more than it does |
| 2.50 ct | 8.5 mm | Statement size |
| 3.00 ct | 9.0 mm | Unmistakably large solitaire |
| 4.00 ct | 10.0 mm | Cocktail-ring territory |
| 5.00 ct | 11.0 mm | Maximum drama — like the center of our Baguette Moissanite 3-Stone Ring in its 5ct version |
One useful quirk: because of how it's cut, a moissanite often faces up slightly larger than a diamond of the same carat weight — another reason to shop by millimeters, not just carats.
Other shapes (approximate, at common cuts)
| Shape | 1 ct | 2 ct | Notes |
|---|---|---|---|
| Oval | 7 × 5 mm | 9 × 7 mm | Elongated shape faces up larger than round at the same weight, and lengthens the look of the finger |
| Emerald | 7 × 5 mm | 8 × 6 mm | Step cuts show size honestly — less sparkle camouflage, more clean geometry (see our 2ct emerald-cut ring: a true 8 × 6 mm look) |
| Cushion | ~6 × 6 mm | ~8 × 7 mm | Soft corners; depth varies by cut, so mm can swing a little |
| Princess | ~5.5–6 mm square | ~7 mm square | Square cuts carry more weight in depth, so they face up a touch smaller than round |
All measurements are approximate — individual stones vary slightly by cut, which is normal for every gemstone, diamond included.
What sizes actually look like on a hand
- Under 1 ct (up to 6.5 mm): refined and everyday-appropriate. In studs, this range — like the smaller sizes of our Moissanite Round Stud Earrings ($27–$112 by size) — reads as a bright point of light rather than a big stone.
- 1–2 ct (6.5–8 mm): the classic engagement-ring presence. Present from across a table, never costume-y.
- 2–3 ct (8–9 mm): the "is that real?" zone — with moissanite's extra fire (see Moissanite Fire, explained), these sizes get noticed constantly.
- 3 ct and up (9 mm+): statement pieces. In men's jewelry and pendants this scale is common and looks intentional; in a ring, know it's a look you're choosing on purpose.
A note on finger coverage
The same stone looks bigger on a smaller hand — a 6.5 mm stone covers a much larger share of a size-5 finger than a size-9. If you're between sizes, that coverage effect is a better guide than carat weight alone. And if you're still deciding between shapes, How to Choose a Moissanite Engagement Ring walks through the decision start to finish.
The bottom line
Shop by millimeters. A "1 carat" that measures 6.5 mm is the honest benchmark; everything else scales from there. Every product page in our store states its stone sizes up front, shipping is free within the US (international is a flat $20 per order, duties calculated at checkout), and the stone you measured on this chart is the stone that shows up.
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