Carat size guide
How big is that carat, really?
Carat is a unit of weight, not size. Here's how different weights compare visually and what actually affects how large a stone looks.
Round brilliant cut — relative sizes
Circles shown at approximate scale. Actual appearance varies by cut, shape, and screen resolution.
0.15 ct
3.4mm
0.25 ct
4.1mm
0.50 ct
5.2mm
0.75 ct
5.9mm
1.00 ct
6.5mm
1.50 ct
7.4mm
2.00 ct
8.2mm
3.00 ct
9.4mm
5.00 ct
11.1mm
Size reference table
Round brilliant cut. Diameter is the key measurement when choosing a stone.
| Carat weight | Diameter (mm) | How it reads | Common use |
|---|---|---|---|
| 0.15 ct | 3.4mm | Very subtle — accent stone territory | Side stones, stacking bands |
| 0.25 ct | 4.1mm | Small but clearly visible | Everyday studs, minimalist solitaires |
| 0.33 ct | 4.4mm | Slightly more presence than 0.25ct | Delicate solitaire rings |
| 0.50 ct | 5.2mm | Visible and balanced — popular everyday size | Solitaire rings, pendants |
| 0.75 ct | 5.9mm | Noticeable without being large | Engagement rings, statement pendants |
| 1.00 ct | 6.5mm | Clear statement — the classic benchmark | Engagement rings |
| 1.25 ct | 6.9mm | Noticeably larger than 1ct | Engagement rings, special pieces |
| 1.50 ct | 7.4mm | Substantial — hard to miss | Statement engagement rings |
| 2.00 ct | 8.2mm | Bold and dramatic | Statement pieces |
| 3.00 ct | 9.4mm | Exceptional size | Custom, special occasion |
| 5.00 ct | 11.1mm | Rare — significant visual presence | Custom only |
Shape affects apparent size
The same carat weight looks different depending on the cut. Some shapes spread the weight across a larger face-up area.
Round
The standard reference cut. Maximum light return and brilliance. Most popular worldwide.
Oval
Appears larger face-up than round at the same carat weight due to its elongated spread.
Cushion
Rounded square with soft corners. Strong fire and a vintage character with modern brilliance.
Pear
Teardrop silhouette. Round top, pointed bottom. Creates a large visual footprint for its carat weight.
Princess
Square with sharp corners and excellent brilliance. The most popular fancy cut after round.
Marquise
Elongated with pointed ends. One of the largest face-up appearances per carat of any shape.
Asscher
Square step cut with cropped corners. Art deco character with a deep, hall-of-mirrors effect.
Emerald Cut
Rectangular step cut with cropped corners. Clean, architectural look. Showcases clarity over brilliance.
Radiant
Rectangular with cropped corners and brilliant faceting. Combines emerald shape with round-style light return.
Heart
A romantic statement cut. Requires skilled cutting for good symmetry. Bold and distinctive.
Baguette
Narrow rectangular step cut. Used almost exclusively as a side stone or accent. Clean and architectural.
Carat measures weight, not size
Two stones with the same carat weight can look completely different depending on their cut proportions and shape. A well-cut 0.70ct will appear larger and more brilliant than a poorly cut 1.00ct. Cut quality has a greater impact on appearance than carat weight.
Shape also changes the visual impression significantly. An oval or pear 0.50ct spreads the stone's weight across a larger surface area and will look noticeably bigger face-up than a round 0.50ct of the same weight.
If you're deciding between sizes or shapes for a specific piece, message us — we can advise based on the design and your finger size.
Shape also changes the visual impression significantly. An oval or pear 0.50ct spreads the stone's weight across a larger surface area and will look noticeably bigger face-up than a round 0.50ct of the same weight.
If you're deciding between sizes or shapes for a specific piece, message us — we can advise based on the design and your finger size.