How big is a 1 carat radiant cut diamond?
By HeyGema™ · Updated
In short
A 1 carat radiant cut diamond measures about 6.5 x 5.0 mm. It faces up 2% smaller than a round diamond of the same weight. On a size 6 finger it covers 30% of the width. For the same weight, a round diamond is 6.5 mm.
- 6.5 x 5.0 mm1 carat radiant
- 0.26 x 0.20 inthe same in inches
- -2%face-up size vs a round
- 30%of a size 6 finger's width
Carat to mm calculator
About 6.5 x 5.0 mm
An estimate for a well-cut stone. A deep or shallow cut faces up smaller or bigger.
1 carat radiant diamond size
A well-cut 1 carat radiant cut diamond measures about 6.5 x 5.0 mm (0.26 x 0.20 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 0.20 grams.
1 carat radiant size by length-to-width ratio
The same weight can be long and narrow or short and wide. These are 1 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: 5.7 x 5.7 mm
- Width on the finger: 35% of a size 6 finger
- 1.15:1
- Length x width: 6.1 x 5.3 mm
- Width on the finger: 32% of a size 6 finger
- 1.30:1
- Length x width: 6.5 x 5.0 mm
- Width on the finger: 30% of a size 6 finger
- 1.40:1
- Length x width: 6.7 x 4.8 mm
- Width on the finger: 29% of a size 6 finger
1 carat radiant on a finger
- 4
- Finger width: 14.9 mm
- Radiant covers: 34%
- 5
- Finger width: 15.7 mm
- Radiant covers: 32%
- 6
- Finger width: 16.5 mm
- Radiant covers: 30%
- 7
- Finger width: 17.3 mm
- Radiant covers: 29%
- 8
- Finger width: 18.1 mm
- Radiant covers: 28%
- 9
- Finger width: 18.9 mm
- Radiant covers: 26%
Radiant sizes near 1 carat
- 0.5 carat
- Length x width: 5.2 x 4.0 mm
- Round of the same weight: 5.1 mm
- 0.75 carat
- Length x width: 5.9 x 4.5 mm
- Round of the same weight: 5.9 mm
- 1 (this page)
- Length x width: 6.5 x 5.0 mm
- Round of the same weight: 6.5 mm
- 1.25 carat
- Length x width: 7.0 x 5.4 mm
- Round of the same weight: 6.9 mm
- 1.5 carat
- Length x width: 7.4 x 5.7 mm
- Round of the same weight: 7.4 mm
1 carat in other shapes
Every row is a well-cut diamond of 1 carat. The last column is the face-up size against the radiant.
- Round
- Length x width: 6.5 mm
- Against radiant: +2%
- Oval
- Length x width: 8.0 x 5.5 mm
- Against radiant: +8%
- Cushion
- Length x width: 5.6 x 5.6 mm
- Against radiant: -12%
- Princess
- Length x width: 5.5 x 5.5 mm
- Against radiant: -6%
- Emerald cut
- Length x width: 7.0 x 5.0 mm
- Against radiant: +6%
- Asscher
- Length x width: 5.5 x 5.5 mm
- Against radiant: -13%
- Pear
- Length x width: 8.5 x 5.5 mm
- Against radiant: same
- Marquise
- Length x width: 10.4 x 5.2 mm
- Against radiant: +19%
- Heart
- Length x width: 6.5 x 6.5 mm
- Against radiant: -15%
- Trillion
- Length x width: 7.0 x 7.0 mm
- Against radiant: -11%
- Baguette
- Length x width: 8.0 x 4.0 mm
- Against radiant: same