Oval vs Marquise diamond size

By HeyGema™ · Updated November 5, 2026

In short

A 1 carat oval measures 8.0 x 5.5 mm and a 1 carat marquise 10.4 x 5.2 mm. At the same weight a marquise faces up about 9% larger than an oval. In face-up terms, 1 carat of oval looks like a 1.09 carat round and 1 carat of marquise like a 1.25 carat round.

8.0 x 5.5 mm1 ct oval
10.4 x 5.2 mm1 ct marquise
+9%marquise face-up vs oval

Carat to mm calculator

ShapeGemCaratLength to width

About 10.4 x 5.2 mm

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

1 ct oval

8.0 x 5.5 mm

1 ct marquise

10.4 x 5.2 mm

Side by side

1 ct oval inside 1 ct marquise

A 1 carat oval and a 1 carat marquise diamond, to the same scale.

Oval vs Marquise diamond size at the same weight

At the same weight a marquise faces up about 9% larger than an oval. A 1 carat oval measures 8.0 x 5.5 mm and a 1 carat marquise 10.4 x 5.2 mm. A 1 carat oval faces up like a 1.09 carat round, and a 1 carat marquise like a 1.25 carat round.

0.5 carat: Oval length x width: 6.3 x 4.4 mm; Marquise length x width: 8.3 x 4.1 mm; Marquise face-up vs oval: +9%

0.75 carat: Oval length x width: 7.3 x 5.0 mm; Marquise length x width: 9.4 x 4.7 mm; Marquise face-up vs oval: +9%

1 carat: Oval length x width: 8.0 x 5.5 mm; Marquise length x width: 10.4 x 5.2 mm; Marquise face-up vs oval: +9%

1.5 carat: Oval length x width: 9.2 x 6.3 mm; Marquise length x width: 11.9 x 6.0 mm; Marquise face-up vs oval: +9%

2 carat: Oval length x width: 10.1 x 6.9 mm; Marquise length x width: 13.1 x 6.6 mm; Marquise face-up vs oval: +9%

3 carat: Oval length x width: 11.5 x 7.9 mm; Marquise length x width: 15.0 x 7.5 mm; Marquise face-up vs oval: +9%

Carat	Oval length x width	Marquise length x width	Marquise face-up vs oval
0.5 carat	6.3 x 4.4 mm	8.3 x 4.1 mm	+9%
0.75 carat	7.3 x 5.0 mm	9.4 x 4.7 mm	+9%
1 carat	8.0 x 5.5 mm	10.4 x 5.2 mm	+9%
1.5 carat	9.2 x 6.3 mm	11.9 x 6.0 mm	+9%
2 carat	10.1 x 6.9 mm	13.1 x 6.6 mm	+9%
3 carat	11.5 x 7.9 mm	15.0 x 7.5 mm	+9%

Oval vs Marquise on a finger

A 1 carat oval covers 33% of the width of a size 6 finger and a 1 carat marquise covers 32%. Long cuts sit along the finger, so their width is what shows across it.

6.0 mm stone on a 16.5 mm finger: it covers 36% of the widthA 1.5 carat marquise on a size 6 finger.

4: Finger width: 14.9 mm; 1.5 ct oval covers: 42%; 1.5 ct marquise covers: 40%

5: Finger width: 15.7 mm; 1.5 ct oval covers: 40%; 1.5 ct marquise covers: 38%

6: Finger width: 16.5 mm; 1.5 ct oval covers: 38%; 1.5 ct marquise covers: 36%

7: Finger width: 17.3 mm; 1.5 ct oval covers: 36%; 1.5 ct marquise covers: 34%

8: Finger width: 18.1 mm; 1.5 ct oval covers: 35%; 1.5 ct marquise covers: 33%

US ring size	Finger width	1.5 ct oval covers	1.5 ct marquise covers
4	14.9 mm	42%	40%
5	15.7 mm	40%	38%
6	16.5 mm	38%	36%
7	17.3 mm	36%	34%
8	18.1 mm	35%	33%

Match the look, not only the carat

Because a marquise of about 0.87 carat faces up like 1 carat of oval, comparing by weight alone hides the difference. Compare millimeters, or put both stones side by side in the size comparison tool.

Oval and Marquise size charts

Full charts from 0.25 to 5 carat: Oval diamond size chart and Marquise diamond size chart.

Questions

At the same weight a marquise faces up about 9% larger than an oval. Face-up area is what you see from above; the marquise has more of it at equal weight.

A 1 carat oval is about 8.0 x 5.5 mm and a 1 carat marquise about 10.4 x 5.2 mm, for a well-cut stone at the usual ratio.

A 2 carat oval is 10.1 x 6.9 mm and a 2 carat marquise is 13.1 x 6.6 mm. Face-up, the marquise is +9% against the oval.

A 1 carat oval covers 33% of the width of a size 6 finger and a 1 carat marquise 32%. The numbers change with ring size and with the stone's length-to-width ratio.