Diamond Size to Carat Weight Chart for Round, Princess, Pear, and More | 31 Jewels Inc.

Diamond Size to Carat Weight Conversion Chart

At 31 Jewels Inc., we understand that the beauty of a diamond lies not just in its sparkle but in the elegance of its form. This guide is designed to help you visualize and understand the relationship between diamond size and carat weight across various popular cuts. Whether you're selecting a piece for yourself or advising a client, this chart will ensure you make informed, confident decisions.

Round Cut Diamond

Round Cut Diamond
Carat Weight Size (mm)
0.05 carats 2.3 mm
0.10 carats 3.0 mm
0.15 carats 3.4 mm
0.20 carats 3.8 mm
0.25 carats 4.0 mm
0.33 carats 4.4 mm
0.40 carats 4.6 mm
0.50 carats 5.0 mm
0.75 carats 5.5 mm
1.00 carats 6.5 mm
1.25 carats 6.9 mm
1.50 carats 7.4 mm
2.00 carats 8.2 mm
2.50 carats 8.8 mm
3.00 carats 9.3 mm

Princess Cut Diamond

Princess Cut Diamond
Carat Weight Size (mm)
0.05 carats 2.3 x 2.3 mm
0.10 carats 3.0 x 3.0 mm
0.15 carats 3.4 x 3.4 mm
0.20 carats 3.8 x 3.8 mm
0.25 carats 4.0 x 4.0 mm
0.33 carats 4.4 x 4.4 mm
0.40 carats 4.6 x 4.6 mm
0.50 carats 5.0 x 5.0 mm
0.75 carats 5.5 x 5.5 mm
1.00 carats 5.9 x 5.9 mm
1.25 carats 6.3 x 6.3 mm
1.50 carats 6.7 x 6.7 mm
2.00 carats 7.3 x 7.3 mm
2.50 carats 7.8 x 7.8 mm
3.00 carats 8.2 x 8.2 mm

Pear Cut Diamond

Pear Cut Diamond
Carat Weight Size (mm)
0.05 carats 3.8 x 2.5 mm
0.10 carats 4.8 x 3.1 mm
0.15 carats 5.5 x 3.5 mm
0.20 carats 6.0 x 3.7 mm
0.25 carats 6.5 x 3.9 mm
0.33 carats 7.0 x 4.2 mm
0.40 carats 7.4 x 4.4 mm
0.50 carats 8.0 x 5.0 mm
0.75 carats 8.8 x 5.5 mm
1.00 carats 9.3 x 5.8 mm
1.25 carats 9.8 x 6.1 mm
1.50 carats 10.3 x 6.5 mm
2.00 carats 11.2 x 6.8 mm
2.50 carats 11.9 x 7.4 mm
3.00 carats 12.4 x 7.9 mm

Oval Cut Diamond

Oval Cut Diamond
Carat Weight Size (mm)
0.05 carats 3.7 x 2.5 mm
0.10 carats 4.9 x 3.1 mm
0.15 carats 5.5 x 3.5 mm
0.20 carats 5.9 x 3.9 mm
0.25 carats 6.5 x 4.2 mm
0.33 carats 7.0 x 4.5 mm
0.40 carats 7.5 x 4.8 mm
0.50 carats 8.0 x 5.0 mm
0.75 carats 9.0 x 5.8 mm
1.00 carats 10.0 x 6.0 mm
1.25 carats 10.5 x 6.5 mm
1.50 carats 11.0 x 7.0 mm
2.00 carats 11.5 x 7.5 mm
2.50 carats 12.0 x 8.0 mm
3.00 carats 13.0 x 8.5 mm

Marquise Cut Diamond

Marquise Cut Diamond
Carat Weight Size (mm)
0.05 carats 4.0 x 2.0 mm
0.10 carats 5.0 x 2.5 mm
0.15 carats 5.8 x 3.0 mm
0.20 carats 6.5 x 3.2 mm
0.25 carats 7.0 x 3.5 mm
0.33 carats 8.0 x 4.0 mm
0.40 carats 9.0 x 4.5 mm
0.50 carats 10.0 x 5.0 mm
0.75 carats 11.0 x 5.5 mm
1.00 carats 12.0 x 6.0 mm
1.25 carats 12.5 x 6.5 mm
1.50 carats 13.0 x 7.0 mm
2.00 carats 14.0 x 7.5 mm
2.50 carats 15.0 x 8.0 mm
3.00 carats 16.0 x 8.5 mm

Emerald Cut Diamond

Emerald Cut Diamond
Carat Weight Size (mm)
0.05 carats 3.5 x 2.5 mm
0.10 carats 4.5 x 3.0 mm
0.15 carats 5.5 x 3.5 mm
0.20 carats 6.0 x 4.0 mm
0.25 carats 6.5 x 4.5 mm
0.33 carats 7.0 x 5.0 mm
0.40 carats 7.5 x 5.5 mm
0.50 carats 8.0 x 6.0 mm
0.75 carats 9.0 x 6.5 mm
1.00 carats 10.0 x 7.0 mm
1.25 carats 10.5 x 7.5 mm
1.50 carats 11.0 x 8.0 mm
2.00 carats 12.0 x 8.5 mm
2.50 carats 13.0 x 9.0 mm
3.00 carats 14.0 x 9.5 mm

Cushion Cut Diamond

Cushion Cut Diamond
Carat Weight Size (mm)
0.05 carats 2.0 x 2.0 mm
0.10 carats 3.0 x 3.0 mm
0.15 carats 3.5 x 3.5 mm
0.20 carats 4.0 x 4.0 mm
0.25 carats 4.5 x 4.5 mm
0.33 carats 5.0 x 5.0 mm
0.40 carats 5.5 x 5.5 mm
0.50 carats 6.0 x 6.0 mm
0.75 carats 6.5 x 6.5 mm
1.00 carats 7.0 x 7.0 mm
1.25 carats 7.5 x 7.5 mm
1.50 carats 8.0 x 8.0 mm
2.00 carats 8.5 x 8.5 mm
2.50 carats 9.0 x 9.0 mm
3.00 carats 9.5 x 9.5 mm

The Math Behind Diamond Carat Weight:

The carat weight of a diamond is a measure of its mass, with one carat equal to 200 milligrams. While the carat weight gives an idea of the diamond's size, the actual visual appearance can vary depending on the cut and proportions of the diamond. For example, a round diamond may appear larger or smaller than another diamond of the same carat weight if its cut proportions differ.

The approximate carat weights provided in our charts are derived from average measurements, making it easier for you to estimate the size of diamonds you're considering. Keep in mind that the depth, table size, and overall shape can all influence the final appearance and weight of a diamond. Our goal is to empower you with the knowledge to choose the perfect piece that celebrates you.

Let 31 Jewels Inc. guide you through the nuances of diamond selection, ensuring that every choice reflects your unique style and sophistication.