Round Diamond Stone Sizing Guide

Timeless and classic, round diamonds offer the highest brilliance reflected by 58 precise facets. Its round shape symbolizes eternity and is the most popular and expensive diamond cut that is perfect for engagement and wedding rings. Our stone sizing chart below shows the standard sizes and matching carat weights for round-cut diamonds to help you find your perfect fit.

For actual stone sizes and measurements, you can download our Round Stone Sizing Guide.

Round Size (mm)	Round Carat Weight	Round Size (mm)	Round Carat Weight
0.8 mm.	0.0025 ct.	7 mm.	1.30 ct.
1 mm.	0.005 ct.	7.3 mm.	1.50 ct.
1.1 mm.	0.0067 ct.	7.5 mm.	1.67 ct.
1.2 mm.	0.009 ct.	7.75 mm.	1.75 ct.
1.25 mm.	0.01 ct.	8 mm.	2.00 ct.
1.3 mm.	0.01 ct.	8.25 mm.	2.11 ct.
1.5 mm.	0.015 ct.	8.5 mm.	2.43 ct.
1.75 mm.	0.02 ct.	8.7 mm.	2.50 ct.
1.8 mm.	0.025 ct.	9 mm.	2.75 ct.
2 mm.	0.03 ct.	9.1 mm.	3.00 ct.
2.2 mm.	0.04 ct.	9.5 mm.	3.35 ct.
2.5 mm.	0.06 ct.	9.75 mm.	3.61 ct.
2.75 mm.	0.08 ct.	10 mm.	3.87 ct.
3 mm.	0.10 ct.	0.25 mm.	4.16 ct.
3.25 mm.	0.14 ct.	10.5 mm.	4.41 ct.
3.5 mm.	0.17 ct.	10.75 mm.	4.57 ct.
3.75 mm.	0.21 ct.	11 mm.	4.91 ct.
4 mm.	0.25 ct.	11.25 mm.	5.49 ct.
4.25 mm.	0.28 ct.	11.5 mm.	5.85 ct.
4.5 mm.	0.36 ct.	12 mm.	6.84 ct.
4.75 mm.	0.44 ct.	12.25 mm.	7.26 ct.
5.0 mm.	0.50 ct.	12.5 mm.	7.36 ct.
5.25 mm.	0.56 ct.	12.75 mm.	7.52 ct.
5.5 mm.	0.66 ct.	13 mm.	8.51 ct.
5.75 mm.	0.75 ct.	13.5 mm.	9.53 ct.
6 mm.	0.84 ct.	14 mm.	10.49 ct.
6.25 mm.	0.93 ct.	15 mm.	12.89 ct.
6.5 mm.	1.00 ct.	16 mm.	16.06 ct.
6.8 mm.	1.25 ct.