A Complete Guide to Diamond Carat Weight and Its Impact on Engagement Rings

When shopping for an engagement ring, one of the most important decisions you'll make is choosing the right diamond. While many factors come into play—such as clarity, cut, and colour—carat weight often tops the list for many buyers.

In short: Carat measures diamond weight (1 carat = 0.2 grams), not size. Visual size depends on cut shape too — an oval looks larger than a round of the same carat. Doubling carat weight typically more than triples price because larger rough stones are exponentially rarer. Most UK engagement rings centre on 0.7-1.5 carat stones.

But what exactly is diamond carat weight, and how does it affect your ring’s appearance, price, and overall impact? In this guide, we’ll explore everything you need to know about diamond carat weight and how to make the best choice for your engagement ring.

What Is Diamond Carat Weight?

Diamond carat weight refers to how much a diamond weighs, but it’s often mistaken for size. Carat weight is measured in metric carats, with one carat equal to 200 milligrams. While a diamond’s weight does influence its size, two diamonds with the same carat weight can appear very different in size depending on their cut.

For example, a well-cut diamond may appear larger than a poorly cut diamond of the same carat weight. The term “carat” originated from the carob seeds that were historically used as a reference for measuring precious gems. Today, it’s one of the standard metrics used to evaluate diamonds.

To explore diamond options, check out diamond engagement rings in various carat weights.