How big is a 5 carat radiant cut diamond?

By HeyGema™ · Updated

In short

A 5 carat radiant cut diamond measures about 11.1 x 8.5 mm. It faces up 2% smaller than a round diamond of the same weight. On a size 6 finger it covers 52% of the width. For the same weight, a round diamond is 11.0 mm.

Carat to mm calculator

About 11.1 x 8.5 mm

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

5 ct radiant
11.1 x 8.5 mm
5 ct round
11.0 mm
Side by side
5 ct radiant inside 5 ct round
A 5 carat radiant diamond beside a 5 carat round, to the same scale.

5 carat radiant diamond size

A well-cut 5 carat radiant cut diamond measures about 11.1 x 8.5 mm (0.44 x 0.34 inches) at a length-to-width ratio of 1.30:1. It faces up 2% smaller than a round diamond of the same weight. It weighs 1.00 grams.

5 carat radiant size by length-to-width ratio

The same weight can be long and narrow or short and wide. These are 5 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: 9.7 x 9.7 mm
Width on the finger: 59% of a size 6 finger
1.15:1
Length x width: 10.5 x 9.1 mm
Width on the finger: 55% of a size 6 finger
1.30:1
Length x width: 11.1 x 8.5 mm
Width on the finger: 52% of a size 6 finger
1.40:1
Length x width: 11.5 x 8.2 mm
Width on the finger: 50% of a size 6 finger

5 carat radiant on a finger

8.5 mm
8.5 mm stone on a 16.5 mm finger: it covers 52% of the widthA 5 carat radiant diamond on a size 6 finger.
4
Finger width: 14.9 mm
Radiant covers: 57%
5
Finger width: 15.7 mm
Radiant covers: 54%
6
Finger width: 16.5 mm
Radiant covers: 52%
7
Finger width: 17.3 mm
Radiant covers: 49%
8
Finger width: 18.1 mm
Radiant covers: 47%
9
Finger width: 18.9 mm
Radiant covers: 45%

Radiant sizes near 5 carat

3.5 carat
Length x width: 9.9 x 7.6 mm
Round of the same weight: 9.8 mm
4 carat
Length x width: 10.3 x 7.9 mm
Round of the same weight: 10.2 mm
5 (this page)
Length x width: 11.1 x 8.5 mm
Round of the same weight: 11.0 mm
6 carat
Length x width: 11.8 x 9.1 mm
Round of the same weight: 11.7 mm
8 carat
Length x width: 13.0 x 10.0 mm
Round of the same weight: 12.9 mm

5 carat in other shapes

Every row is a well-cut diamond of 5 carat. The last column is the face-up size against the radiant.

Round
Length x width: 11.0 mm
Against radiant: +2%
Oval
Length x width: 13.7 x 9.4 mm
Against radiant: +8%
Cushion
Length x width: 9.6 x 9.6 mm
Against radiant: -12%
Princess
Length x width: 9.4 x 9.4 mm
Against radiant: -6%
Emerald cut
Length x width: 12.0 x 8.5 mm
Against radiant: +6%
Asscher
Length x width: 9.4 x 9.4 mm
Against radiant: -13%
Pear
Length x width: 14.5 x 9.4 mm
Against radiant: same
Marquise
Length x width: 17.8 x 8.9 mm
Against radiant: +19%
Heart
Length x width: 11.1 x 11.1 mm
Against radiant: -15%
Trillion
Length x width: 12.0 x 12.0 mm
Against radiant: -11%
Baguette
Length x width: 13.7 x 6.8 mm
Against radiant: same

Questions

A 5 carat radiant cut diamond is about 11.1 x 8.5 mm at the usual 1.30:1 ratio.
No. Face-up, a 5 carat radiant is 2% smaller than a 5 carat round (11.0 mm).
There is no rule. The stone is 57% of the width of a size 4 finger and 47% 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