Understanding Diamond Carat Weight

"Carat" is the standard unit used to describe a diamond's weight.
To put it into perspective:
1 Carat = 0.20 grams = 200 milligrams

Diamonds are also commonly measured in "points."
100 points = 1 carat, so a 0.50 carat diamond is often called a "50-pointer."

The abbreviation “ct” is used for carat weight.

Carat is a measurement of weight, it should be noted it is not a measurement of size. However, carat is usually relative to size so the higher the carat the larger the stone.

This does not mean though that every diamond of same carat will be exactly the same size. For example, two 0.50 carat stones can be slightly different sizes.

The cut and shape proportions of a diamond can affect the size of one diamond compared to another. We can always provide some approximate or average measurements for every shape diamond in every carat size.

Use our interactive diamond size guide to get a better view on how different diamond shapes and weights will look. You can also view more information on each diamond with the menu button on the left.

Carat vs. Karat – Know the Difference
Don’t confuse carat with karat. While carat (ct) refers to the weight of a diamond, karat (kt) is used to describe the purity of gold - for instance, 9 karat gold means the metal is 37.5% pure gold mixed with other alloys.

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Why Are Diamonds So Rare?
Creating a single 1-carat diamond can require the mining of up to 250 tons of rock. This intensive process contributes to the rarity of diamonds—and, in turn, their value. Simply put, the rarer the diamond, the higher the price.

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Carat Weight Doesn’t Mean Double the Size
A common misconception is that doubling the carat weight of a diamond means doubling its size. For example, people often assume a 0.80 ct diamond is twice the size of a 0.40 ct diamond—but that’s not true.

In reality, while 1 carat is double the weight of 0.50 carat, it’s not twice the physical size. On average, the difference in diameter is only about 1.5mm, depending on the cut and shape.

So remember—carat affects weight, not necessarily the look or spread of the stone.

 

Shape vs Cut: What’s the Difference?

These terms are often used interchangeably, but they mean very different things.

• Shape is the outline or form of the diamond—like Round, Princess, Oval, etc.

• Cut refers to how well the diamond has been faceted and proportioned to reflect light. A well-cut diamond will sparkle brilliantly, regardless of shape.

Diamond Carat & Shape

The shape and cut of a diamond play a significant role in how large a stone appears—not just how much it weighs. For instance, elongated shapes like Oval, Marquise, and Emerald can create the illusion of a larger stone when compared to rounder shapes like Cushion, even if both weigh the same in carats. This is simply because they span more of the finger.

These elongated styles are also a flattering choice for those with longer, slender fingers, creating an elegant and balanced look.

Don’t forget to factor in ring size when selecting your carat weight. A 1-carat diamond will look more prominent on a size J ring finger than on a size Q, due to the difference in finger surface area.

Your lifestyle and personal style matter too. Does the wearer prefer bold, standout pieces, or a more subtle, classic aesthetic?

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Diamond Carat & Price

Carat weight is one of the most impactful factors affecting a diamond’s price. Unlike a straight-line increase, diamond prices jump exponentially as carat size increases. In some cases, doubling the carat weight can triple, quadruple, or even sextuple the price.

For example, all other characteristics being equal, a 1.00 ct diamond will cost more than a 0.97 ct or 0.91 ct stone. However, if color, clarity, or cut differs, it’s possible for a slightly smaller diamond to be more expensive than a full-carat stone.

It all comes down to what matters most to you—size, quality, or a balance of both. Some people are happy with visible inclusions and a slight tint in color as long as they’re getting a 1 ct stone. Others prefer higher quality in smaller sizes, like a 0.50 ct VS2, F color diamond with excellent cut.

Lab-grown diamonds are also worth considering—they offer better value across the 4 Cs and can make it easier to get more carat, clarity, and color within your budget.

If you're looking to reduce cost without compromising visual appeal, adjusting carat weight slightly can make a difference. Opting for a 0.90 ct instead of a 1 ct, for instance, can save you a significant amount, with only a 0.25mm difference in size.

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Understanding Carat Display

Always be aware of how carat weight is displayed, especially when browsing jewelry online:

• Solitaire Rings: The carat refers to the single main stone only.

• Solitaire with Side Stones: The main stone carat is shown, and additional carat for side stones is listed separately in the product description.

• Halo, Three-Stone Rings, and Earrings: Usually presented as T.C.W (Total Carat Weight)—the combined weight of all diamonds.

If you're unsure about what you're seeing, don’t hesitate to ask for a breakdown.

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Final Notes on Visual Impact

Certain settings and styles can enhance how large a diamond appears:

• Halo settings use smaller diamonds around a center stone to amplify its size and brilliance. When perfectly matched, they can even give the illusion of being a single, larger diamond.

• Band width affects visual size too—a thinner band (like 1.8mm) makes the diamond pop more than a thicker one (3mm).

• Tapered bands, which narrow as they approach the stone, can draw the eye toward the diamond and make it appear larger.

Among the 4 Cs (Carat, Cut, Clarity, Color), carat usually makes the biggest visual impact. Still, what matters most is how it looks on your hand and whether it suits your personal preferences.

There’s no one-size-fits-all approach. Some prioritize size first and adjust other features to fit their budget. Others start with quality and let the carat weight fall into place.

No right or wrong—just what’s right for you.