Radiant vs Emerald cut diamond size

By HeyGema™ · Updated November 5, 2026

In short

A 1 carat radiant measures 6.5 x 5.0 mm and a 1 carat emerald cut 7.0 x 5.0 mm. At the same weight an emerald cut faces up about 6% larger than a radiant. In face-up terms, 1 carat of radiant looks like a 0.96 carat round and 1 carat of emerald cut like a 1.06 carat round.

6.5 x 5.0 mm1 ct radiant
7.0 x 5.0 mm1 ct emerald cut
+6%emerald cut face-up vs radiant

Carat to mm calculator

ShapeGemCaratLength to width

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 radiant

6.5 x 5.0 mm

1 ct emerald cut

7.0 x 5.0 mm

Side by side

1 ct radiant inside 1 ct emerald cut

A 1 carat radiant and a 1 carat emerald cut diamond, to the same scale.

Radiant vs Emerald cut diamond size at the same weight

At the same weight an emerald cut faces up about 6% larger than a radiant. A 1 carat radiant measures 6.5 x 5.0 mm and a 1 carat emerald cut 7.0 x 5.0 mm. A 1 carat radiant faces up like a 0.96 carat round, and a 1 carat emerald cut like a 1.06 carat round.

0.5 carat: Radiant length x width: 5.2 x 4.0 mm; Emerald cut length x width: 5.6 x 4.0 mm; Emerald cut face-up vs radiant: +6%

0.75 carat: Radiant length x width: 5.9 x 4.5 mm; Emerald cut length x width: 6.4 x 4.5 mm; Emerald cut face-up vs radiant: +6%

1 carat: Radiant length x width: 6.5 x 5.0 mm; Emerald cut length x width: 7.0 x 5.0 mm; Emerald cut face-up vs radiant: +6%

1.5 carat: Radiant length x width: 7.4 x 5.7 mm; Emerald cut length x width: 8.0 x 5.7 mm; Emerald cut face-up vs radiant: +6%

2 carat: Radiant length x width: 8.2 x 6.3 mm; Emerald cut length x width: 8.8 x 6.3 mm; Emerald cut face-up vs radiant: +6%

3 carat: Radiant length x width: 9.4 x 7.2 mm; Emerald cut length x width: 10.1 x 7.2 mm; Emerald cut face-up vs radiant: +6%

Carat	Radiant length x width	Emerald cut length x width	Emerald cut face-up vs radiant
0.5 carat	5.2 x 4.0 mm	5.6 x 4.0 mm	+6%
0.75 carat	5.9 x 4.5 mm	6.4 x 4.5 mm	+6%
1 carat	6.5 x 5.0 mm	7.0 x 5.0 mm	+6%
1.5 carat	7.4 x 5.7 mm	8.0 x 5.7 mm	+6%
2 carat	8.2 x 6.3 mm	8.8 x 6.3 mm	+6%
3 carat	9.4 x 7.2 mm	10.1 x 7.2 mm	+6%

Radiant vs Emerald cut on a finger

A 1 carat radiant covers 30% of the width of a size 6 finger and a 1 carat emerald cut covers 30%. Long cuts sit along the finger, so their width is what shows across it.

5.7 mm stone on a 16.5 mm finger: it covers 35% of the widthA 1.5 carat emerald cut on a size 6 finger.

4: Finger width: 14.9 mm; 1.5 ct radiant covers: 38%; 1.5 ct emerald cut covers: 38%

5: Finger width: 15.7 mm; 1.5 ct radiant covers: 36%; 1.5 ct emerald cut covers: 36%

6: Finger width: 16.5 mm; 1.5 ct radiant covers: 35%; 1.5 ct emerald cut covers: 35%

7: Finger width: 17.3 mm; 1.5 ct radiant covers: 33%; 1.5 ct emerald cut covers: 33%

8: Finger width: 18.1 mm; 1.5 ct radiant covers: 32%; 1.5 ct emerald cut covers: 32%

US ring size	Finger width	1.5 ct radiant covers	1.5 ct emerald cut covers
4	14.9 mm	38%	38%
5	15.7 mm	36%	36%
6	16.5 mm	35%	35%
7	17.3 mm	33%	33%
8	18.1 mm	32%	32%

Match the look, not only the carat

Because an emerald cut of about 0.91 carat faces up like 1 carat of radiant, comparing by weight alone hides the difference. Compare millimeters, or put both stones side by side in the size comparison tool.

Radiant and Emerald cut size charts

Full charts from 0.25 to 5 carat: Radiant diamond size chart and Emerald cut diamond size chart.

Questions

At the same weight an emerald cut faces up about 6% larger than a radiant. Face-up area is what you see from above; the emerald cut has more of it at equal weight.

A 1 carat radiant is about 6.5 x 5.0 mm and a 1 carat emerald cut about 7.0 x 5.0 mm, for a well-cut stone at the usual ratio.

A 2 carat radiant is 8.2 x 6.3 mm and a 2 carat emerald cut is 8.8 x 6.3 mm. Face-up, the emerald cut is +6% against the radiant.

A 1 carat radiant covers 30% of the width of a size 6 finger and a 1 carat emerald cut 30%. The numbers change with ring size and with the stone's length-to-width ratio.