How big is a 0.33 carat cushion cut diamond?

By HeyGema™ · Updated

In short

A 0.33 carat cushion cut diamond measures about 3.9 x 3.9 mm. It faces up 14% smaller than a round diamond of the same weight. On a size 6 finger it covers 23% of the width. For the same weight, a round diamond is 4.5 mm.

Carat to mm calculator

About 3.9 x 3.9 mm

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

0.33 ct cushion
3.9 x 3.9 mm
0.33 ct round
4.5 mm
Side by side
0.33 ct cushion inside 0.33 ct round
A 0.33 carat cushion diamond beside a 0.33 carat round, to the same scale.

0.33 carat cushion diamond size

A well-cut 0.33 carat cushion cut diamond measures about 3.9 x 3.9 mm (0.15 x 0.15 inches) at a length-to-width ratio of 1.00:1. It faces up 14% smaller than a round diamond of the same weight. It weighs 0.066 grams.

0.33 carat cushion size by length-to-width ratio

The same weight can be long and narrow or short and wide. These are 0.33 carat sizes at each ratio. A longer ratio runs the stone along the finger and makes it look slimmer. The face-up area stays almost the same.

1.00:1
Length x width: 3.9 x 3.9 mm
Width on the finger: 23% of a size 6 finger
1.10:1
Length x width: 4.1 x 3.7 mm
Width on the finger: 22% of a size 6 finger
1.20:1
Length x width: 4.2 x 3.5 mm
Width on the finger: 21% of a size 6 finger
1.30:1
Length x width: 4.4 x 3.4 mm
Width on the finger: 21% of a size 6 finger

0.33 carat cushion on a finger

3.9 mm
3.9 mm stone on a 16.5 mm finger: it covers 23% of the widthA 0.33 carat cushion diamond on a size 6 finger.
4
Finger width: 14.9 mm
Cushion covers: 26%
5
Finger width: 15.7 mm
Cushion covers: 25%
6
Finger width: 16.5 mm
Cushion covers: 23%
7
Finger width: 17.3 mm
Cushion covers: 22%
8
Finger width: 18.1 mm
Cushion covers: 21%
9
Finger width: 18.9 mm
Cushion covers: 20%

Cushion sizes near 0.33 carat

0.25 carat
Length x width: 3.5 x 3.5 mm
Round of the same weight: 4.1 mm
0.33 (this page)
Length x width: 3.9 x 3.9 mm
Round of the same weight: 4.5 mm
0.5 carat
Length x width: 4.4 x 4.4 mm
Round of the same weight: 5.1 mm
0.75 carat
Length x width: 5.1 x 5.1 mm
Round of the same weight: 5.9 mm

0.33 carat in other shapes

Every row is a well-cut diamond of 0.33 carat. The last column is the face-up size against the cushion.

Round
Length x width: 4.5 mm
Against cushion: +16%
Oval
Length x width: 5.5 x 3.8 mm
Against cushion: +23%
Princess
Length x width: 3.8 x 3.8 mm
Against cushion: +7%
Emerald cut
Length x width: 4.8 x 3.5 mm
Against cushion: +21%
Asscher
Length x width: 3.8 x 3.8 mm
Against cushion: -2%
Radiant
Length x width: 4.5 x 3.5 mm
Against cushion: +14%
Pear
Length x width: 5.9 x 3.8 mm
Against cushion: +13%
Marquise
Length x width: 7.2 x 3.6 mm
Against cushion: +35%
Heart
Length x width: 4.5 x 4.5 mm
Against cushion: -4%
Trillion
Length x width: 4.8 x 4.8 mm
Against cushion: +1%
Baguette
Length x width: 5.5 x 2.76 mm
Against cushion: +14%

Questions

A 0.33 carat cushion cut diamond is about 3.9 x 3.9 mm at the usual 1.00:1 ratio.
No. Face-up, a 0.33 carat cushion is 14% smaller than a 0.33 carat round (4.5 mm).
There is no rule. The stone is 26% of the width of a size 4 finger and 21% of a size 8. Compare it with a ring you have tried on in the finger chart above.
Yes. A lab grown diamond has the same density as a mined one, so it measures the same for the same weight.

More size charts