Cabochon-cut Tanzanite Size Chart
Carat to mm size chart for cabochon-cut Tanzanite, 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:
Tanzanite Size Chart (Cabochon Cut)
0.25ct
4.58×3.05 mm
4.58×3.05 mm
0.5ct
5.76×3.84 mm
5.76×3.84 mm
0.75ct
6.6×4.4 mm
6.6×4.4 mm
1ct
7.26×4.84 mm
7.26×4.84 mm
1.25ct
7.82×5.21 mm
7.82×5.21 mm
1.5ct
8.31×5.54 mm
8.31×5.54 mm
1.75ct
8.75×5.83 mm
8.75×5.83 mm
2ct
9.15×6.1 mm
9.15×6.1 mm
2.5ct
9.86×6.57 mm
9.86×6.57 mm
3ct
10.47×6.98 mm
10.47×6.98 mm
3.5ct
11.03×7.35 mm
11.03×7.35 mm
4ct
11.52×7.68 mm
11.52×7.68 mm
4.5ct
11.99×7.99 mm
11.99×7.99 mm
5ct
12.42×8.28 mm
12.42×8.28 mm
5.5ct
12.81×8.54 mm
12.81×8.54 mm
6ct
13.2×8.8 mm
13.2×8.8 mm
6.5ct
13.55×9.03 mm
13.55×9.03 mm
7ct
13.89×9.26 mm
13.89×9.26 mm
7.5ct
14.21×9.47 mm
14.21×9.47 mm
8ct
14.52×9.68 mm
14.52×9.68 mm
8.5ct
14.82×9.88 mm
14.82×9.88 mm
9ct
15.11×10.07 mm
15.11×10.07 mm
9.5ct
15.38×10.25 mm
15.38×10.25 mm
10ct
15.65×10.43 mm
15.65×10.43 mm
11ct
16.14×10.76 mm
16.14×10.76 mm
12ct
16.62×11.08 mm
16.62×11.08 mm
13ct
17.07×11.38 mm
17.07×11.38 mm
14ct
17.51×11.67 mm
17.51×11.67 mm
15ct
17.91×11.94 mm
17.91×11.94 mm
16ct
18.3×12.2 mm
18.3×12.2 mm
17ct
18.68×12.45 mm
18.68×12.45 mm
18ct
19.02×12.68 mm
19.02×12.68 mm
19ct
19.38×12.92 mm
19.38×12.92 mm
20ct
19.71×13.14 mm
19.71×13.14 mm
22ct
20.34×13.56 mm
20.34×13.56 mm
24ct
20.94×13.96 mm
20.94×13.96 mm
26ct
21.51×14.34 mm
21.51×14.34 mm
28ct
22.05×14.7 mm
22.05×14.7 mm
30ct
22.56×15.04 mm
22.56×15.04 mm
33ct
23.3×15.53 mm
23.3×15.53 mm
36ct
23.97×15.98 mm
23.97×15.98 mm
40ct
24.83×16.55 mm
24.83×16.55 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 Tanzanite carat weights to their approximate millimeter (mm) sizes:
| Carat Weight | MM Size |
|---|---|
| 0.25 ct | 4.58×3.05 mm |
| 0.5 ct | 5.76×3.84 mm |
| 0.75 ct | 6.6×4.4 mm |
| 1 ct | 7.26×4.84 mm |
| 1.25 ct | 7.82×5.21 mm |
| 1.5 ct | 8.31×5.54 mm |
| 1.75 ct | 8.75×5.83 mm |
| 2 ct | 9.15×6.1 mm |
| 2.5 ct | 9.86×6.57 mm |
| 3 ct | 10.47×6.98 mm |
| 3.5 ct | 11.03×7.35 mm |
| 4 ct | 11.52×7.68 mm |
| 4.5 ct | 11.99×7.99 mm |
| 5 ct | 12.42×8.28 mm |
| 5.5 ct | 12.81×8.54 mm |
| 6 ct | 13.2×8.8 mm |
| 6.5 ct | 13.55×9.03 mm |
| 7 ct | 13.89×9.26 mm |
| 7.5 ct | 14.21×9.47 mm |
| 8 ct | 14.52×9.68 mm |
| 8.5 ct | 14.82×9.88 mm |
| Carat Weight | MM Size |
|---|---|
| 9 ct | 15.11×10.07 mm |
| 9.5 ct | 15.38×10.25 mm |
| 10 ct | 15.65×10.43 mm |
| 11 ct | 16.14×10.76 mm |
| 12 ct | 16.62×11.08 mm |
| 13 ct | 17.07×11.38 mm |
| 14 ct | 17.51×11.67 mm |
| 15 ct | 17.91×11.94 mm |
| 16 ct | 18.3×12.2 mm |
| 17 ct | 18.68×12.45 mm |
| 18 ct | 19.02×12.68 mm |
| 19 ct | 19.38×12.92 mm |
| 20 ct | 19.71×13.14 mm |
| 22 ct | 20.34×13.56 mm |
| 24 ct | 20.94×13.96 mm |
| 26 ct | 21.51×14.34 mm |
| 28 ct | 22.05×14.7 mm |
| 30 ct | 22.56×15.04 mm |
| 33 ct | 23.3×15.53 mm |
| 36 ct | 23.97×15.98 mm |
| 40 ct | 24.83×16.55 mm |