Short answer: A 1.0 mm round melee is roughly 0.005 ct, 1.5 mm ≈ 0.015 ct, 2.0 mm ≈ 0.03 ct, 2.5 mm ≈ 0.06 ct, and 3.0 mm ≈ 0.10 ct. Moissanite weighs slightly less than diamond at the same mm, so always order accent stones by millimeter, not carat, for setting accuracy.
Round melee reference
Stone counts below are the actual counts in a Caratura 1-carat bag, so what you read here is what arrives.
| Diameter | Diamond wt (ct, approx.) | Stones per 1-ct bag |
|---|---|---|
| 0.8 mm | ~0.0025 | ~340 |
| 1.0 mm | ~0.005 | ~200 |
| 1.2 mm | ~0.0085 | ~125 |
| 1.3 mm | ~0.01 | ~100 |
| 1.5 mm | ~0.015 | ~70 |
| 1.7 mm | ~0.02 | ~50 |
| 2.0 mm | ~0.03 | ~35 |
| 2.5 mm | ~0.06 | ~17 |
| 3.0 mm | ~0.10 | ~10 |
Weights are approximate and vary with cut and depth. Moissanite is about 10% lighter than diamond at the same diameter — another reason to spec by mm. Every 0.1 mm step from 0.7–3.0 mm is stocked; the full list is on the round melee product page.
Need the same conversion for fancy shapes, or for stones above 3 mm? The mm to carat chart for all 14 shapes covers oval, pear, princess, baguette, trapezoid and the rest, melee to 10 ct.
Practical tip
Settings are made to mm, so order melee by diameter and let weight follow. For mixed pavé, list quantity per mm.
Replacing a single stone in an existing piece rather than setting new? See how to size and match a replacement melee stone.
By Leilei, founder of Caratura — every bag is one size, calibrated to ±0.1 mm, with about 20% of stones rejected by hand before it ships. Every price is published: $28 per 1-carat bag, no minimum, no price list, no quote. WhatsApp me with the size you need for a stock check.