How big is a 0.25 carat oval diamond?

By HeyGema™ · Updated

In short

A 0.25 carat oval diamond measures about 5.0 x 3.5 mm. It faces up 6% bigger than a round diamond of the same weight. On a size 6 finger it covers 21% of the width. For the same weight, a round diamond is 4.1 mm.

Carat to mm calculator

About 5.0 x 3.5 mm

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

0.25 ct oval
5.0 x 3.5 mm
0.25 ct round
4.1 mm
Side by side
0.25 ct round inside 0.25 ct oval
A 0.25 carat oval diamond beside a 0.25 carat round, to the same scale.

0.25 carat oval diamond size

A well-cut 0.25 carat oval diamond measures about 5.0 x 3.5 mm (0.20 x 0.14 inches) at a length-to-width ratio of 1.45:1. It faces up 6% bigger than a round diamond of the same weight. It weighs 0.050 grams.

0.25 carat oval size by length-to-width ratio

The same weight can be long and narrow or short and wide. These are 0.25 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.

1.25:1
Length x width: 4.7 x 3.7 mm
Width on the finger: 23% of a size 6 finger
1.35:1
Length x width: 4.9 x 3.6 mm
Width on the finger: 22% of a size 6 finger
1.45:1
Length x width: 5.0 x 3.5 mm
Width on the finger: 21% of a size 6 finger
1.55:1
Length x width: 5.2 x 3.4 mm
Width on the finger: 20% of a size 6 finger

0.25 carat oval on a finger

3.5 mm
3.5 mm stone on a 16.5 mm finger: it covers 21% of the widthA 0.25 carat oval diamond on a size 6 finger.
4
Finger width: 14.9 mm
Oval covers: 23%
5
Finger width: 15.7 mm
Oval covers: 22%
6
Finger width: 16.5 mm
Oval covers: 21%
7
Finger width: 17.3 mm
Oval covers: 20%
8
Finger width: 18.1 mm
Oval covers: 19%
9
Finger width: 18.9 mm
Oval covers: 18%

Oval sizes near 0.25 carat

0.25 (this page)
Length x width: 5.0 x 3.5 mm
Round of the same weight: 4.1 mm
0.33 carat
Length x width: 5.5 x 3.8 mm
Round of the same weight: 4.5 mm
0.5 carat
Length x width: 6.3 x 4.4 mm
Round of the same weight: 5.1 mm

0.25 carat in other shapes

Every row is a well-cut diamond of 0.25 carat. The last column is the face-up size against the oval.

Round
Length x width: 4.1 mm
Against oval: -5%
Cushion
Length x width: 3.5 x 3.5 mm
Against oval: -19%
Princess
Length x width: 3.5 x 3.5 mm
Against oval: -13%
Emerald cut
Length x width: 4.4 x 3.1 mm
Against oval: -2%
Asscher
Length x width: 3.5 x 3.5 mm
Against oval: -20%
Radiant
Length x width: 4.1 x 3.1 mm
Against oval: -8%
Pear
Length x width: 5.4 x 3.5 mm
Against oval: -8%
Marquise
Length x width: 6.6 x 3.3 mm
Against oval: +9%
Heart
Length x width: 4.1 x 4.1 mm
Against oval: -22%
Trillion
Length x width: 4.4 x 4.4 mm
Against oval: -18%
Baguette
Length x width: 5.0 x 2.52 mm
Against oval: -7%

Questions

A 0.25 carat oval diamond is about 5.0 x 3.5 mm at the usual 1.45:1 ratio.
Yes. Face-up, a 0.25 carat oval is 6% bigger than a 0.25 carat round (4.1 mm).
There is no rule. The stone is 23% of the width of a size 4 finger and 19% 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