How big is a 6 carat cushion cut diamond?

By HeyGema™ · Updated

In short

A 6 carat cushion cut diamond measures about 10.2 x 10.2 mm. It faces up 14% smaller than a round diamond of the same weight. On a size 6 finger it covers 62% of the width. For the same weight, a round diamond is 11.7 mm.

Carat to mm calculator

About 10.2 x 10.2 mm

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

6 ct cushion
10.2 x 10.2 mm
6 ct round
11.7 mm
Side by side
6 ct cushion inside 6 ct round
A 6 carat cushion diamond beside a 6 carat round, to the same scale.

6 carat cushion diamond size

A well-cut 6 carat cushion cut diamond measures about 10.2 x 10.2 mm (0.40 x 0.40 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 1.20 grams.

6 carat cushion size by length-to-width ratio

The same weight can be long and narrow or short and wide. These are 6 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: 10.2 x 10.2 mm
Width on the finger: 62% of a size 6 finger
1.10:1
Length x width: 10.7 x 9.7 mm
Width on the finger: 59% of a size 6 finger
1.20:1
Length x width: 11.1 x 9.3 mm
Width on the finger: 56% of a size 6 finger
1.30:1
Length x width: 11.6 x 8.9 mm
Width on the finger: 54% of a size 6 finger

6 carat cushion on a finger

10.2 mm
10.2 mm stone on a 16.5 mm finger: it covers 62% of the widthA 6 carat cushion diamond on a size 6 finger.
4
Finger width: 14.9 mm
Cushion covers: 68%
5
Finger width: 15.7 mm
Cushion covers: 65%
6
Finger width: 16.5 mm
Cushion covers: 62%
7
Finger width: 17.3 mm
Cushion covers: 59%
8
Finger width: 18.1 mm
Cushion covers: 56%
9
Finger width: 18.9 mm
Cushion covers: 54%

Cushion sizes near 6 carat

4 carat
Length x width: 8.9 x 8.9 mm
Round of the same weight: 10.2 mm
5 carat
Length x width: 9.6 x 9.6 mm
Round of the same weight: 11.0 mm
6 (this page)
Length x width: 10.2 x 10.2 mm
Round of the same weight: 11.7 mm
8 carat
Length x width: 11.2 x 11.2 mm
Round of the same weight: 12.9 mm
10 carat
Length x width: 12.1 x 12.1 mm
Round of the same weight: 13.9 mm

6 carat in other shapes

Every row is a well-cut diamond of 6 carat. The last column is the face-up size against the cushion.

Round
Length x width: 11.7 mm
Against cushion: +16%
Oval
Length x width: 14.5 x 10.0 mm
Against cushion: +23%
Princess
Length x width: 10.0 x 10.0 mm
Against cushion: +7%
Emerald cut
Length x width: 12.7 x 9.1 mm
Against cushion: +21%
Asscher
Length x width: 10.0 x 10.0 mm
Against cushion: -2%
Radiant
Length x width: 11.8 x 9.1 mm
Against cushion: +14%
Pear
Length x width: 15.4 x 10.0 mm
Against cushion: +13%
Marquise
Length x width: 18.9 x 9.4 mm
Against cushion: +35%
Heart
Length x width: 11.8 x 11.8 mm
Against cushion: -4%
Trillion
Length x width: 12.7 x 12.7 mm
Against cushion: +1%
Baguette
Length x width: 14.5 x 7.3 mm
Against cushion: +14%

Questions

A 6 carat cushion cut diamond is about 10.2 x 10.2 mm at the usual 1.00:1 ratio.
No. Face-up, a 6 carat cushion is 14% smaller than a 6 carat round (11.7 mm).
There is no rule. The stone is wider than most fingers. 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