How big is a 1 carat cubic zirconia?

By HeyGema™ · Updated

In short

A 1 carat round cubic zirconia measures about 5.5 mm across (0.21 inches), 15% narrower than a 1 carat diamond (6.5 mm). An oval of the same weight is 6.8 x 4.7 mm and an emerald cut 5.9 x 4.2 mm.

Carat to mm calculator

About 5.5 x 5.5 mm

An estimate for a well-cut stone. A deep or shallow cut faces up smaller or bigger.

Round
5.5 mm
Oval
6.8 x 4.7 mm
Cushion
4.7 x 4.7 mm
Princess
4.7 x 4.7 mm
Emerald cut
5.9 x 4.2 mm
Asscher
4.7 x 4.7 mm
Radiant
5.5 x 4.2 mm
Pear
7.2 x 4.7 mm
Marquise
8.8 x 4.4 mm
Heart
5.5 x 5.5 mm
Trillion
5.9 x 5.9 mm
Baguette
6.8 x 3.4 mm
= 2 mm in every picture above
A 1 carat cubic zirconia in 12 shapes, drawn to one scale.

1 carat cubic zirconia size by shape

Face-up measurements of a well-cut 1 carat cubic zirconia. Cubic zirconia is denser than diamond (5.80 against 3.52), so it packs more weight into less space and faces up 15% narrower for the same weight.

Round
Length x width: 5.5 mm
In inches: 0.21 in
Oval
Length x width: 6.8 x 4.7 mm
In inches: 0.27 x 0.18 in
Cushion
Length x width: 4.7 x 4.7 mm
In inches: 0.19 x 0.19 in
Princess
Length x width: 4.7 x 4.7 mm
In inches: 0.18 x 0.18 in
Emerald cut
Length x width: 5.9 x 4.2 mm
In inches: 0.23 x 0.17 in
Asscher
Length x width: 4.7 x 4.7 mm
In inches: 0.18 x 0.18 in
Radiant
Length x width: 5.5 x 4.2 mm
In inches: 0.22 x 0.17 in
Pear
Length x width: 7.2 x 4.7 mm
In inches: 0.28 x 0.18 in
Marquise
Length x width: 8.8 x 4.4 mm
In inches: 0.35 x 0.17 in
Heart
Length x width: 5.5 x 5.5 mm
In inches: 0.22 x 0.22 in
Trillion
Length x width: 5.9 x 5.9 mm
In inches: 0.23 x 0.23 in
Baguette
Length x width: 6.8 x 3.4 mm
In inches: 0.27 x 0.13 in

1 carat cubic zirconia against other gems

Diamond
Round, 1 carat: 6.5 mm
Moissanite
Round, 1 carat: 6.6 mm
Sapphire
Round, 1 carat: 6.2 mm
Ruby
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
Cubic zirconia (this page)
Round, 1 carat: 5.5 mm

1 carat cubic zirconia on a finger

5.5 mm
5.5 mm stone on a 16.5 mm finger: it covers 33% of the widthA round 1 carat cubic zirconia on a size 6 finger.
4
Finger width: 14.9 mm
Round covers: 37%
Oval covers: 31%
5
Finger width: 15.7 mm
Round covers: 35%
Oval covers: 30%
6
Finger width: 16.5 mm
Round covers: 33%
Oval covers: 28%
7
Finger width: 17.3 mm
Round covers: 32%
Oval covers: 27%
8
Finger width: 18.1 mm
Round covers: 30%
Oval covers: 26%
9
Finger width: 18.9 mm
Round covers: 29%
Oval covers: 25%

Cubic zirconia at nearby weights

0.5 carat cubic zirconia
Round diameter: 4.3 mm
1 ct (this page)
Round diameter: 5.5 mm
1.5 carat cubic zirconia
Round diameter: 6.3 mm

Questions

A round 1 carat cubic zirconia is about 5.5 mm across. Other shapes are longer than they are wide: an oval is 6.8 x 4.7 mm.
No. A round 1 carat cubic zirconia is 15% narrower than a 1 carat diamond (6.5 mm).
0.20 grams. A carat is 200 milligrams for every gem.
A round 1 carat cubic zirconia covers 33% of the width of a size 6 finger. Compare it with a ring you have tried on in the finger chart above.

More size charts