Convert diamond measurements to estimated carat weight, or a target weight to millimeter dimensions, across 20+ shapes using GIA-standard proportions. Built for the trade.
1 — Select Shape
2 — Enter Measurements
Length
mm
Width
mm
Bottom Width
mm
Length × Width in millimeters.
Advanced: exact depth & girdle ▾
Depth (mm)
mm
Girdle
Depth defaults to the shape's standard % (leave blank). Girdle defaults to medium; thicker adds hidden weight without adding face-up size.
2 — Enter Target Weight
ct
We solve for millimeter dimensions using the shape's standard length-to-width ratio and depth.
Length-to-Width Ratio
L:W
Adjust to match your desired outline. 1.00 = square/round.
Select a shape and enter measurements to see the estimate.
How it works: weight = length × width × depth × a shape factor, following GIA proportions. Estimates land within about ±5–7% of scaled weight; actual cut, bulge and girdle vary. Use as a production and buying guide, not a substitute for a scale.
Need calibrated stones or custom layouts? Call or WhatsApp +1 (646) 370-6567 | sales@priyagrown.com
