How big is a 1 carat ruby?
By HeyGema™ · Updated
In short
A 1 carat round ruby measures about 6.2 mm across (0.24 inches), 4% narrower than a 1 carat diamond (6.5 mm). An oval of the same weight is 7.7 x 5.3 mm and an emerald cut 6.7 x 4.8 mm.
- 6.2 mmround ruby, across
- 0.24 inthe same in inches
- 0.20 gweight
- 37%of a size 6 finger's width
Carat to mm calculator
About 6.2 x 6.2 mm
An estimate for a well-cut stone. A deep or shallow cut faces up smaller or bigger.
Round
6.2 mm
Oval
7.7 x 5.3 mm
Cushion
5.4 x 5.4 mm
Princess
5.3 x 5.3 mm
Emerald cut
6.7 x 4.8 mm
Asscher
5.3 x 5.3 mm
Radiant
6.2 x 4.8 mm
Pear
8.1 x 5.3 mm
Marquise
10.0 x 5.0 mm
Heart
6.2 x 6.2 mm
Trillion
6.7 x 6.7 mm
Baguette
7.7 x 3.8 mm
= 2 mm in every picture above
1 carat ruby size by shape
Face-up measurements of a well-cut 1 carat ruby. Ruby is denser than diamond (4.00 against 3.52), so it packs more weight into less space and faces up 4% narrower for the same weight.
- Round
- Length x width: 6.2 mm
- In inches: 0.24 in
- Oval
- Length x width: 7.7 x 5.3 mm
- In inches: 0.30 x 0.21 in
- Cushion
- Length x width: 5.4 x 5.4 mm
- In inches: 0.21 x 0.21 in
- Princess
- Length x width: 5.3 x 5.3 mm
- In inches: 0.21 x 0.21 in
- Emerald cut
- Length x width: 6.7 x 4.8 mm
- In inches: 0.26 x 0.19 in
- Asscher
- Length x width: 5.3 x 5.3 mm
- In inches: 0.21 x 0.21 in
- Radiant
- Length x width: 6.2 x 4.8 mm
- In inches: 0.25 x 0.19 in
- Pear
- Length x width: 8.1 x 5.3 mm
- In inches: 0.32 x 0.21 in
- Marquise
- Length x width: 10.0 x 5.0 mm
- In inches: 0.39 x 0.20 in
- Heart
- Length x width: 6.2 x 6.2 mm
- In inches: 0.25 x 0.25 in
- Trillion
- Length x width: 6.7 x 6.7 mm
- In inches: 0.26 x 0.26 in
- Baguette
- Length x width: 7.7 x 3.8 mm
- In inches: 0.30 x 0.15 in
1 carat ruby against other gems
- Diamond
- Round, 1 carat: 6.5 mm
- Moissanite
- Round, 1 carat: 6.6 mm
- Sapphire
- Round, 1 carat: 6.2 mm
- Emerald
- Round, 1 carat: 7.0 mm
- Aquamarine
- Round, 1 carat: 7.0 mm
- Morganite
- Round, 1 carat: 7.0 mm
- Tanzanite
- Round, 1 carat: 6.6 mm
- Topaz
- Round, 1 carat: 6.4 mm
- Ruby (this page)
- Round, 1 carat: 6.2 mm
1 carat ruby on a finger
- 4
- Finger width: 14.9 mm
- Round covers: 42%
- Oval covers: 35%
- 5
- Finger width: 15.7 mm
- Round covers: 39%
- Oval covers: 34%
- 6
- Finger width: 16.5 mm
- Round covers: 37%
- Oval covers: 32%
- 7
- Finger width: 17.3 mm
- Round covers: 36%
- Oval covers: 30%
- 8
- Finger width: 18.1 mm
- Round covers: 34%
- Oval covers: 29%
- 9
- Finger width: 18.9 mm
- Round covers: 33%
- Oval covers: 28%
Ruby at nearby weights
- 0.5 carat ruby
- Round diameter: 4.9 mm
- 1 ct (this page)
- Round diameter: 6.2 mm
- 1.5 carat ruby
- Round diameter: 7.1 mm
Questions
A round 1 carat ruby is about 6.2 mm across. Other shapes are longer than they are wide: an oval is 7.7 x 5.3 mm.
No. A round 1 carat ruby is 4% narrower than a 1 carat diamond (6.5 mm).
0.20 grams. A carat is 200 milligrams for every gem.
A round 1 carat ruby covers 37% of the width of a size 6 finger. Compare it with a ring you have tried on in the finger chart above.