How big is a 1 carat emerald cut diamond?

By HeyGema™ · Updated

In short

A 1 carat emerald cut diamond measures about 7.0 x 5.0 mm. It faces up 4% bigger 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.

Carat to mm calculator

About 7.0 x 5.0 mm

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

1 ct emerald cut
7.0 x 5.0 mm
1 ct round
6.5 mm
Side by side
1 ct emerald cut inside 1 ct round
A 1 carat emerald cut diamond beside a 1 carat round, to the same scale.

1 carat emerald cut diamond size

A well-cut 1 carat emerald cut diamond measures about 7.0 x 5.0 mm (0.28 x 0.20 inches) at a length-to-width ratio of 1.40:1. It faces up 4% bigger than a round diamond of the same weight. It weighs 0.20 grams.

1 carat emerald cut 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.

1.30:1
Length x width: 6.7 x 5.2 mm
Width on the finger: 31% of a size 6 finger
1.40:1
Length x width: 7.0 x 5.0 mm
Width on the finger: 30% of a size 6 finger
1.50:1
Length x width: 7.2 x 4.8 mm
Width on the finger: 29% of a size 6 finger
1.60:1
Length x width: 7.5 x 4.7 mm
Width on the finger: 28% of a size 6 finger

1 carat emerald cut on a finger

5.0 mm
5.0 mm stone on a 16.5 mm finger: it covers 30% of the widthA 1 carat emerald cut diamond on a size 6 finger.
4
Finger width: 14.9 mm
Emerald cut covers: 34%
5
Finger width: 15.7 mm
Emerald cut covers: 32%
6
Finger width: 16.5 mm
Emerald cut covers: 30%
7
Finger width: 17.3 mm
Emerald cut covers: 29%
8
Finger width: 18.1 mm
Emerald cut covers: 28%
9
Finger width: 18.9 mm
Emerald cut covers: 26%

Emerald cut sizes near 1 carat

0.5 carat
Length x width: 5.6 x 4.0 mm
Round of the same weight: 5.1 mm
0.75 carat
Length x width: 6.4 x 4.5 mm
Round of the same weight: 5.9 mm
1 (this page)
Length x width: 7.0 x 5.0 mm
Round of the same weight: 6.5 mm
1.25 carat
Length x width: 7.5 x 5.4 mm
Round of the same weight: 6.9 mm
1.5 carat
Length x width: 8.0 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 emerald cut.

Round
Length x width: 6.5 mm
Against emerald cut: -4%
Oval
Length x width: 8.0 x 5.5 mm
Against emerald cut: +2%
Cushion
Length x width: 5.6 x 5.6 mm
Against emerald cut: -17%
Princess
Length x width: 5.5 x 5.5 mm
Against emerald cut: -11%
Asscher
Length x width: 5.5 x 5.5 mm
Against emerald cut: -19%
Radiant
Length x width: 6.5 x 5.0 mm
Against emerald cut: -6%
Pear
Length x width: 8.5 x 5.5 mm
Against emerald cut: -6%
Marquise
Length x width: 10.4 x 5.2 mm
Against emerald cut: +12%
Heart
Length x width: 6.5 x 6.5 mm
Against emerald cut: -20%
Trillion
Length x width: 7.0 x 7.0 mm
Against emerald cut: -17%
Baguette
Length x width: 8.0 x 4.0 mm
Against emerald cut: -6%

Questions

A 1 carat emerald cut diamond is about 7.0 x 5.0 mm at the usual 1.40:1 ratio.
Yes. Face-up, a 1 carat emerald cut is 4% bigger than a 1 carat round (6.5 mm).
There is no rule. The stone is 34% of the width of a size 4 finger and 28% 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