How big is a 4 carat sapphire?
By HeyGema™ · Updated
In short
A 4 carat round sapphire measures about 9.8 mm across (0.39 inches), 4% narrower than a 4 carat diamond (10.2 mm). An oval of the same weight is 12.2 x 8.4 mm and an emerald cut 10.6 x 7.6 mm.
- 9.8 mmround sapphire, across
- 0.39 inthe same in inches
- 0.80 gweight
- 59%of a size 6 finger's width
Carat to mm calculator
About 9.8 x 9.8 mm
An estimate for a well-cut stone. A deep or shallow cut faces up smaller or bigger.
Round
9.8 mm
Oval
12.2 x 8.4 mm
Cushion
8.5 x 8.5 mm
Princess
8.4 x 8.4 mm
Emerald cut
10.6 x 7.6 mm
Asscher
8.4 x 8.4 mm
Radiant
9.9 x 7.6 mm
Pear
12.9 x 8.4 mm
Marquise
15.8 x 7.9 mm
Heart
9.9 x 9.9 mm
Trillion
10.6 x 10.6 mm
Baguette
12.2 x 6.1 mm
= 5 mm in every picture above
4 carat sapphire size by shape
Face-up measurements of a well-cut 4 carat sapphire. Sapphire is denser than diamond (4.00 against 3.52), so it packs more weight into less space and faces up 4% narrower for the same weight.
- Round
- Length x width: 9.8 mm
- In inches: 0.39 in
- Oval
- Length x width: 12.2 x 8.4 mm
- In inches: 0.48 x 0.33 in
- Cushion
- Length x width: 8.5 x 8.5 mm
- In inches: 0.34 x 0.34 in
- Princess
- Length x width: 8.4 x 8.4 mm
- In inches: 0.33 x 0.33 in
- Emerald cut
- Length x width: 10.6 x 7.6 mm
- In inches: 0.42 x 0.30 in
- Asscher
- Length x width: 8.4 x 8.4 mm
- In inches: 0.33 x 0.33 in
- Radiant
- Length x width: 9.9 x 7.6 mm
- In inches: 0.39 x 0.30 in
- Pear
- Length x width: 12.9 x 8.4 mm
- In inches: 0.51 x 0.33 in
- Marquise
- Length x width: 15.8 x 7.9 mm
- In inches: 0.62 x 0.31 in
- Heart
- Length x width: 9.9 x 9.9 mm
- In inches: 0.39 x 0.39 in
- Trillion
- Length x width: 10.6 x 10.6 mm
- In inches: 0.42 x 0.42 in
- Baguette
- Length x width: 12.2 x 6.1 mm
- In inches: 0.48 x 0.24 in
4 carat sapphire against other gems
- Diamond
- Round, 4 carat: 10.2 mm
- Moissanite
- Round, 4 carat: 10.5 mm
- Ruby
- Round, 4 carat: 9.8 mm
- Emerald
- Round, 4 carat: 11.2 mm
- Aquamarine
- Round, 4 carat: 11.2 mm
- Morganite
- Round, 4 carat: 11.1 mm
- Tanzanite
- Round, 4 carat: 10.4 mm
- Topaz
- Round, 4 carat: 10.2 mm
- Sapphire (this page)
- Round, 4 carat: 9.8 mm
4 carat sapphire on a finger
- 4
- Finger width: 14.9 mm
- Round covers: 66%
- Oval covers: 56%
- 5
- Finger width: 15.7 mm
- Round covers: 63%
- Oval covers: 53%
- 6
- Finger width: 16.5 mm
- Round covers: 59%
- Oval covers: 51%
- 7
- Finger width: 17.3 mm
- Round covers: 57%
- Oval covers: 48%
- 8
- Finger width: 18.1 mm
- Round covers: 54%
- Oval covers: 46%
- 9
- Finger width: 18.9 mm
- Round covers: 52%
- Oval covers: 44%
Sapphire at nearby weights
- 3 carat sapphire
- Round diameter: 8.9 mm
- 4 ct (this page)
- Round diameter: 9.8 mm
- 5 carat sapphire
- Round diameter: 10.6 mm
Questions
A round 4 carat sapphire is about 9.8 mm across. Other shapes are longer than they are wide: an oval is 12.2 x 8.4 mm.
No. A round 4 carat sapphire is 4% narrower than a 4 carat diamond (10.2 mm).
0.80 grams. A carat is 200 milligrams for every gem.
A round 4 carat sapphire covers 59% of the width of a size 6 finger. Compare it with a ring you have tried on in the finger chart above.