Cabochon-cut Tourmaline Size Chart
Carat to mm size chart for cabochon-cut Tourmaline, from 0.25ct to 40ct (at an L/W ratio of 1.5). The chart is interactive, meaning you can click on any stone to view it directly in the size simulator.
Gem sizes are shown in actual, real-world size, provided your device screen size is in diagonal. If this is not correct, change it here:
Gem sizes are shown in actual, real-world size, provided your device screen size is in diagonal. If this is not correct, change it here:
Actual size is set for screen
Gemstone:
Shape:
Tourmaline Size Chart (Cabochon Cut)
0.25ct
4.71×3.14 mm
4.71×3.14 mm
0.5ct
5.94×3.96 mm
5.94×3.96 mm
0.75ct
6.8×4.53 mm
6.8×4.53 mm
1ct
7.49×4.99 mm
7.49×4.99 mm
1.25ct
8.06×5.37 mm
8.06×5.37 mm
1.5ct
8.57×5.71 mm
8.57×5.71 mm
1.75ct
9.02×6.01 mm
9.02×6.01 mm
2ct
9.44×6.29 mm
9.44×6.29 mm
2.5ct
10.16×6.77 mm
10.16×6.77 mm
3ct
10.79×7.19 mm
10.79×7.19 mm
3.5ct
11.36×7.57 mm
11.36×7.57 mm
4ct
11.88×7.92 mm
11.88×7.92 mm
4.5ct
12.36×8.24 mm
12.36×8.24 mm
5ct
12.8×8.53 mm
12.8×8.53 mm
5.5ct
13.22×8.81 mm
13.22×8.81 mm
6ct
13.59×9.06 mm
13.59×9.06 mm
6.5ct
13.97×9.31 mm
13.97×9.31 mm
7ct
14.31×9.54 mm
14.31×9.54 mm
7.5ct
14.64×9.76 mm
14.64×9.76 mm
8ct
14.97×9.98 mm
14.97×9.98 mm
8.5ct
15.27×10.18 mm
15.27×10.18 mm
9ct
15.57×10.38 mm
15.57×10.38 mm
9.5ct
15.86×10.57 mm
15.86×10.57 mm
10ct
16.13×10.75 mm
16.13×10.75 mm
11ct
16.64×11.09 mm
16.64×11.09 mm
12ct
17.13×11.42 mm
17.13×11.42 mm
13ct
17.6×11.73 mm
17.6×11.73 mm
14ct
18.03×12.02 mm
18.03×12.02 mm
15ct
18.45×12.3 mm
18.45×12.3 mm
16ct
18.86×12.57 mm
18.86×12.57 mm
17ct
19.25×12.83 mm
19.25×12.83 mm
18ct
19.61×13.07 mm
19.61×13.07 mm
19ct
19.97×13.31 mm
19.97×13.31 mm
20ct
20.31×13.54 mm
20.31×13.54 mm
22ct
20.97×13.98 mm
20.97×13.98 mm
24ct
21.59×14.39 mm
21.59×14.39 mm
26ct
22.17×14.78 mm
22.17×14.78 mm
28ct
22.73×15.15 mm
22.73×15.15 mm
30ct
23.25×15.5 mm
23.25×15.5 mm
33ct
24×16 mm
24×16 mm
36ct
24.71×16.47 mm
24.71×16.47 mm
40ct
25.59×17.06 mm
25.59×17.06 mm
Length-to-width ratio: 1.5, Color:
Download Chart
Note: If you want to cut out the shapes and try them on your finger, print out the PDF chart. The image (png) chart will not print at actual size.
Carat-to-MM Conversion Table
Use this conversion table to quickly convert cabochon-cut Tourmaline carat weights to their approximate millimeter (mm) sizes:
| Carat Weight | MM Size |
|---|---|
| 0.25 ct | 4.71×3.14 mm |
| 0.5 ct | 5.94×3.96 mm |
| 0.75 ct | 6.8×4.53 mm |
| 1 ct | 7.49×4.99 mm |
| 1.25 ct | 8.06×5.37 mm |
| 1.5 ct | 8.57×5.71 mm |
| 1.75 ct | 9.02×6.01 mm |
| 2 ct | 9.44×6.29 mm |
| 2.5 ct | 10.16×6.77 mm |
| 3 ct | 10.79×7.19 mm |
| 3.5 ct | 11.36×7.57 mm |
| 4 ct | 11.88×7.92 mm |
| 4.5 ct | 12.36×8.24 mm |
| 5 ct | 12.8×8.53 mm |
| 5.5 ct | 13.22×8.81 mm |
| 6 ct | 13.59×9.06 mm |
| 6.5 ct | 13.97×9.31 mm |
| 7 ct | 14.31×9.54 mm |
| 7.5 ct | 14.64×9.76 mm |
| 8 ct | 14.97×9.98 mm |
| 8.5 ct | 15.27×10.18 mm |
| Carat Weight | MM Size |
|---|---|
| 9 ct | 15.57×10.38 mm |
| 9.5 ct | 15.86×10.57 mm |
| 10 ct | 16.13×10.75 mm |
| 11 ct | 16.64×11.09 mm |
| 12 ct | 17.13×11.42 mm |
| 13 ct | 17.6×11.73 mm |
| 14 ct | 18.03×12.02 mm |
| 15 ct | 18.45×12.3 mm |
| 16 ct | 18.86×12.57 mm |
| 17 ct | 19.25×12.83 mm |
| 18 ct | 19.61×13.07 mm |
| 19 ct | 19.97×13.31 mm |
| 20 ct | 20.31×13.54 mm |
| 22 ct | 20.97×13.98 mm |
| 24 ct | 21.59×14.39 mm |
| 26 ct | 22.17×14.78 mm |
| 28 ct | 22.73×15.15 mm |
| 30 ct | 23.25×15.5 mm |
| 33 ct | 24×16 mm |
| 36 ct | 24.71×16.47 mm |
| 40 ct | 25.59×17.06 mm |