Round Diamond Size and Carat Weight

Carat Weight vs. Size

Carat is a unit of weight used to measure diamonds, but it does not directly equate to a diamond's size. For round brilliant diamonds, carat weight is often used as an indicator of size because the weight correlates with the diamond's diameter when viewed from above.

Size Dimensions

A 1-carat round diamond, for example, typically has a diameter of approximately 6.4–6.5 mm, assuming an ideal cut.

However, a diamond's size can appear smaller or larger depending on its cut proportions. For instance:

• Shallow Cuts: May have a wider diameter but less depth.
• Deep Cuts: May appear smaller because more of the carat weight is in the depth rather than the visible surface.

Perceived Size

The size of a round diamond is also affected by its setting and surrounding design. Halo settings or thin bands can make a diamond appear larger, while thicker bands may have the opposite effect.

In summary, while carat weight provides a baseline for the diamond’s size, the cut, proportions, and setting play an essential role in its visual impact.