1.5 carat vs 2.5 carat diamond size
By HeyGema™ · Updated
In short
A round 2.5 carat diamond measures 8.8 mm and a round 1.5 carat 7.4 mm. The 2.5 carat is 1.67 times the weight but only 19% wider (1.4 mm), with 41% more face-up area.
- 7.4 vs 8.8 mmround diameter
- 19%wider at 2.5 ct
- 41%more face-up area
Carat to mm calculator
About 8.8 x 8.8 mm
An estimate for a well-cut stone. A deep or shallow cut faces up smaller or bigger.
1.5 carat vs 2.5 carat: how much bigger is it?
A 2.5 carat diamond weighs 1.67 times the weight of a 1.5 carat, but it is only 19% wider. A round 1.5 carat measures 7.4 mm and a round 2.5 carat 8.8 mm, a difference of 1.4 mm. Seen from above, the 2.5 carat covers 41% more area.
The gap is smaller than the weights suggest because carats measure weight, which grows with volume. A stone that is twice as heavy is the cube root of two (1.26 times) as wide, not twice as wide.
1.5 carat and 2.5 carat in every shape
- Round
- 1.5 carat: 7.4 mm
- 2.5 carat: 8.8 mm
- Longer by: 1.4 mm
- Oval
- 1.5 carat: 9.2 x 6.3 mm
- 2.5 carat: 10.9 x 7.5 mm
- Longer by: 1.7 mm
- Cushion
- 1.5 carat: 6.4 x 6.4 mm
- 2.5 carat: 7.6 x 7.6 mm
- Longer by: 1.2 mm
- Princess
- 1.5 carat: 6.3 x 6.3 mm
- 2.5 carat: 7.5 x 7.5 mm
- Longer by: 1.2 mm
- Emerald cut
- 1.5 carat: 8.0 x 5.7 mm
- 2.5 carat: 9.5 x 6.8 mm
- Longer by: 1.5 mm
- Pear
- 1.5 carat: 9.7 x 6.3 mm
- 2.5 carat: 11.5 x 7.5 mm
- Longer by: 1.8 mm
- Marquise
- 1.5 carat: 11.9 x 6.0 mm
- 2.5 carat: 14.1 x 7.1 mm
- Longer by: 2.2 mm
- Radiant
- 1.5 carat: 7.4 x 5.7 mm
- 2.5 carat: 8.8 x 6.8 mm
- Longer by: 1.4 mm
- Asscher
- 1.5 carat: 6.3 x 6.3 mm
- 2.5 carat: 7.5 x 7.5 mm
- Longer by: 1.2 mm
- Heart
- 1.5 carat: 7.4 x 7.4 mm
- 2.5 carat: 8.8 x 8.8 mm
- Longer by: 1.4 mm
1.5 carat vs 2.5 carat on a finger
- 4
- Finger width: 14.9 mm
- Round 1.5 ct covers: 50%
- Round 2.5 ct covers: 59%
- 5
- Finger width: 15.7 mm
- Round 1.5 ct covers: 47%
- Round 2.5 ct covers: 56%
- 6
- Finger width: 16.5 mm
- Round 1.5 ct covers: 45%
- Round 2.5 ct covers: 53%
- 7
- Finger width: 17.3 mm
- Round 1.5 ct covers: 43%
- Round 2.5 ct covers: 51%
- 8
- Finger width: 18.1 mm
- Round 1.5 ct covers: 41%
- Round 2.5 ct covers: 48%
On a size 6 finger the 1.5 carat reads as bold (45% of the width) and the 2.5 carat as bold (53%). The bands are our own: delicate is under 30% of the finger's width, classic is 30% to 44%, bold is 45% to 59%, statement is 60% and more.
Other cuts at 1.5 and 2.5 carat
Shape changes the picture. An oval or a pear of 1.5 carat can face up as large as a round of a higher weight. See the shapes that look biggest, or compare any two stones with the size comparison tool.