How big is a 1.75 carat princess cut diamond?

By HeyGema™ · Updated November 5, 2026

In short

A 1.75 carat princess cut diamond measures about 6.6 x 6.6 mm. It faces up 8% smaller than a round diamond of the same weight. On a size 6 finger it covers 40% of the width. For the same weight, a round diamond is 7.8 mm.

6.6 x 6.6 mm1.75 carat princess
0.26 x 0.26 inthe same in inches
-8%face-up size vs a round
40%of a size 6 finger's width

Carat to mm calculator

ShapeGemCarat

About 6.6 x 6.6 mm

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

1.75 ct princess

6.6 x 6.6 mm

1.75 ct round

7.8 mm

Side by side

1.75 ct princess inside 1.75 ct round

A 1.75 carat princess diamond beside a 1.75 carat round, to the same scale.

1.75 carat princess diamond size

A well-cut 1.75 carat princess cut diamond measures about 6.6 x 6.6 mm (0.26 x 0.26 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 0.35 grams.

1.75 carat princess on a finger

6.6 mm stone on a 16.5 mm finger: it covers 40% of the widthA 1.75 carat princess diamond on a size 6 finger.

4: Finger width: 14.9 mm; Princess covers: 45%

5: Finger width: 15.7 mm; Princess covers: 42%

6: Finger width: 16.5 mm; Princess covers: 40%

7: Finger width: 17.3 mm; Princess covers: 38%

8: Finger width: 18.1 mm; Princess covers: 37%

9: Finger width: 18.9 mm; Princess covers: 35%

US ring size	Finger width	Princess covers
4	14.9 mm	45%
5	15.7 mm	42%
6	16.5 mm	40%
7	17.3 mm	38%
8	18.1 mm	37%
9	18.9 mm	35%

Princess sizes near 1.75 carat

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

1.75 (this page): Length x width: 6.6 x 6.6 mm; Round of the same weight: 7.8 mm

2 carat: Length x width: 6.9 x 6.9 mm; Round of the same weight: 8.1 mm

2.25 carat: Length x width: 7.2 x 7.2 mm; Round of the same weight: 8.5 mm

Carat	Length x width	Round of the same weight
1.25 carat	5.9 x 5.9 mm	6.9 mm
1.5 carat	6.3 x 6.3 mm	7.4 mm
1.75 (this page)	6.6 x 6.6 mm	7.8 mm
2 carat	6.9 x 6.9 mm	8.1 mm
2.25 carat	7.2 x 7.2 mm	8.5 mm

1.75 carat in other shapes

Every row is a well-cut diamond of 1.75 carat. The last column is the face-up size against the princess.

Round: Length x width: 7.8 mm; Against princess: +9%

Oval: Length x width: 9.6 x 6.6 mm; Against princess: +15%

Cushion: Length x width: 6.7 x 6.7 mm; Against princess: -6%

Emerald cut: Length x width: 8.4 x 6.0 mm; Against princess: +13%

Asscher: Length x width: 6.6 x 6.6 mm; Against princess: -8%

Radiant: Length x width: 7.8 x 6.0 mm; Against princess: +6%

Pear: Length x width: 10.2 x 6.6 mm; Against princess: +6%

Marquise: Length x width: 12.5 x 6.3 mm; Against princess: +26%

Heart: Length x width: 7.8 x 7.8 mm; Against princess: -10%

Trillion: Length x width: 8.4 x 8.4 mm; Against princess: -6%

Baguette: Length x width: 9.6 x 4.8 mm; Against princess: +7%

Shape	Length x width	Against princess
Round	7.8 mm	+9%
Oval	9.6 x 6.6 mm	+15%
Cushion	6.7 x 6.7 mm	-6%
Emerald cut	8.4 x 6.0 mm	+13%
Asscher	6.6 x 6.6 mm	-8%
Radiant	7.8 x 6.0 mm	+6%
Pear	10.2 x 6.6 mm	+6%
Marquise	12.5 x 6.3 mm	+26%
Heart	7.8 x 7.8 mm	-10%
Trillion	8.4 x 8.4 mm	-6%
Baguette	9.6 x 4.8 mm	+7%

Questions

A 1.75 carat princess cut diamond is about 6.6 x 6.6 mm at the usual 1.00:1 ratio.

No. Face-up, a 1.75 carat princess is 8% smaller than a 1.75 carat round (7.8 mm).

There is no rule. The stone is 45% of the width of a size 4 finger and 37% 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.