How big is a 1 carat princess cut diamond?
By HeyGema™ · Updated
In short
A 1 carat princess cut diamond measures about 5.5 x 5.5 mm. It faces up 8% smaller than a round diamond of the same weight. On a size 6 finger it covers 33% of the width. For the same weight, a round diamond is 6.5 mm.
- 5.5 x 5.5 mm1 carat princess
- 0.22 x 0.22 inthe same in inches
- -8%face-up size vs a round
- 33%of a size 6 finger's width
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.
1 ct princess
5.5 x 5.5 mm
1 ct round
6.5 mm
Side by side
1 ct princess inside 1 ct round
1 carat princess diamond size
A well-cut 1 carat princess cut diamond measures about 5.5 x 5.5 mm (0.22 x 0.22 inches) at a length-to-width ratio of 1.00:1. It faces up 8% smaller than a round diamond of the same weight. It weighs 0.20 grams.
1 carat princess on a finger
- 4
- Finger width: 14.9 mm
- Princess covers: 37%
- 5
- Finger width: 15.7 mm
- Princess covers: 35%
- 6
- Finger width: 16.5 mm
- Princess covers: 33%
- 7
- Finger width: 17.3 mm
- Princess covers: 32%
- 8
- Finger width: 18.1 mm
- Princess covers: 30%
- 9
- Finger width: 18.9 mm
- Princess covers: 29%
Princess sizes near 1 carat
- 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: 5.0 x 5.0 mm
- Round of the same weight: 5.9 mm
- 1 (this page)
- Length x width: 5.5 x 5.5 mm
- Round of the same weight: 6.5 mm
- 1.25 carat
- Length x width: 5.9 x 5.9 mm
- Round of the same weight: 6.9 mm
- 1.5 carat
- Length x width: 6.3 x 6.3 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 princess.
- Round
- Length x width: 6.5 mm
- Against princess: +9%
- Oval
- Length x width: 8.0 x 5.5 mm
- Against princess: +15%
- Cushion
- Length x width: 5.6 x 5.6 mm
- Against princess: -6%
- Emerald cut
- Length x width: 7.0 x 5.0 mm
- Against princess: +13%
- Asscher
- Length x width: 5.5 x 5.5 mm
- Against princess: -8%
- Radiant
- Length x width: 6.5 x 5.0 mm
- Against princess: +6%
- Pear
- Length x width: 8.5 x 5.5 mm
- Against princess: +6%
- Marquise
- Length x width: 10.4 x 5.2 mm
- Against princess: +26%
- Heart
- Length x width: 6.5 x 6.5 mm
- Against princess: -10%
- Trillion
- Length x width: 7.0 x 7.0 mm
- Against princess: -6%
- Baguette
- Length x width: 8.0 x 4.0 mm
- Against princess: +7%
Questions
A 1 carat princess cut diamond is about 5.5 x 5.5 mm at the usual 1.00:1 ratio.
No. Face-up, a 1 carat princess is 8% smaller than a 1 carat round (6.5 mm).
There is no rule. The stone is 37% of the width of a size 4 finger and 30% 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.