What Is CTTW for Diamonds?

If you are looking for diamond earrings offline or online, you will see the tag CTTW along with cut quality, color, clarity, and carat. You might be wondering what this term represents.

CTTW stands for Carat Total Weight. In this article, I will discuss total carat weight and how it differs from the carat weight of a diamond.

What Is CTTW for Diamonds

Carat Weight

The symbol CT signifies carat weight. It is the weight of a diamond and is equal to 0.2 grams or 200 milligrams.

Raw diamonds lose almost half of their size during cutting, shaping, and polishing, and ultimately whatever is left is used in jewelry. The weight of the leftover stone is evaluated in carats. 

Who Determines Carat Weight?

In reputed laboratories like the American Gem Society and Gemological Institute of America, the weight of the diamond is measured on a highly accurate and calibrated scale. So, you should always purchase diamonds that are certified by such institutions.

Carat weight differs by a diamond shape. Shapes like oval, pear, heart, cushion, or emerald will have different carat weights for the same diameter of the diamond. A diamond can have a high carat weight even if it does not look bigger on your finger. 

Moreover, two diamonds having the same carat weight can differ in their size if one diamond is cut deeper compared to another.

Does Carat Weight Determine the Price of a Diamond?

The price of a diamond does not depend on the carat weight alone. It is difficult to approximate the price of a diamond just from its carat weight. Other features like cut quality, color, and clarity play a role in determining the final price of a diamond.

Interestingly, the word carat was derived from Ceratonia Siliqua, also known as the Carob tree. In earlier days, when there was no weighing scale, diamond merchants matched the weight of a diamond with the seed of a Carob tree. 

Total Carat Weight (CTTW)

Total carat weight or CTTW signifies the total of all the diamonds’ individual carat weights in your ring, necklace, or another piece of jewelry.

How To Measure CTTW

If you intend to purchase an engagement ring with a centerpiece diamond of 1-carat and two side diamonds, each weighing 0.3 carats, the total carat weight is 1 + 0.3 + 0.3 = 1.6 CTTW.

If you intend to purchase a sapphire ring, the total carat weight does not include the gemstone weight. It includes the weight of the accent diamonds in the ring. 

Again, if you purchase diamond earrings, you should divide the total carat weight on the tag by two to determine the diamond size in each earring.

What Is CTTW Used For?

The total carat weight helps you compare diamond rings. Moreover, dividing the price of the diamond ring by the total carat weight will help you determine the price per carat, which will help you find a cheaper diamond ring.

A large diamond stone may cost you more per carat than smaller diamonds because larger diamonds are rarer. 

Two diamond rings of the same total carat weight may differ in price because of differences in quality. For instance, a carat diamond with lower color and clarity grade will be cheaper than a carat weight diamond of high clarity and color grade.

Some reputed laboratories use technologies to create diamonds with the same physical characteristics as natural diamonds. These lab-grown diamonds are quite affordable compared to natural ones. One of the online diamond jewelers I recommend is James Allen.

Many people who want to wear diamonds but have a lower budget can wear lab-grown diamonds. Lab-grown diamonds are also presented with a tag for carat and total carat weight.


James Allen Logo

James Allen is our most recommended online jeweler that guarantees a wonderful online shopping experience. You will find the most beautiful and best quality diamonds available for very competitive prices.

What Is the Difference Between Carat Weight (CT) and Total Carat Weight (CTTW)?

CTTW stands for the total carat weight. It is the total weight of all the diamonds in a single piece of jewelry. For instance, in engagement rings, bracelets, or necklaces, you may find many small diamonds surrounding a large diamond. CTTW will tell you about the summation of the weight of all the diamonds in the ring.

CTTW does not help you in determining the total price of the jewelry. This is because the price of a diamond is not always proportional to its carat weight. 

For example, a single large 1-carat diamond is rare and commands a higher premium. So its price will be much higher than the sum of five small diamonds, each of 0.2-carat weight, even though the CTTW will be the same for two rings having these configurations.

Let us understand this in more detail.

Other Factors That Determine The Price Of a Diamond

How Can Color Change the Cost of a One Carat Diamond?

The color is one of the most determining factors affecting the price of the diamond. The Gemological Institute of America provides color grading, which starts from D and ends with Z. The color D indicates that the diamond is colorless. If you purchase a diamond closer to Z, the diamond will have a degree of yellow or brown tint.

If you purchase a 1-carat diamond of D color grade, it will be a bit more expensive than a 1-carat diamond with an N or S color grade.

How Can Clarity Change the Cost of a One Carat Diamond?

Clarity means impurities in the diamond. Remember, almost all diamonds have impurities when examined under a high-power microscope. The Gemological Institute of America has graded clarity in various ways:

  • Flawless: Neither blemishes nor inclusions are seen under 10× magnification
  • Internal flawless: Only blemishes are seen under 10× magnification.
  • Very very slightly included: Inclusions are quite challenging to see in a 10× magnification.
  • Very slightly included: Impurities are minor.
  • Slightly included: Impurities are seen in 10× magnification
  • Inclusions: Impurities are easily visible under 10× magnification and affect the brilliance of a diamond.

If you intend to purchase a 1-carat diamond with a lower clarity grade like SI, it will cost you less than a one-carat diamond with a higher clarity grade like VVS1 or VVS2.

How Cut Quality Affects the Cost of a One Carat Diamond

Cut quality dramatically affects the final price of the diamond. The polish and symmetry of the diamond are two major components of the cut quality. 

A diamond can have maximum brilliance if every facet is polished after the cutting process. Asymmetrical diamonds have well-aligned facets.

Some people tend to focus only on carat weight while purchasing a diamond. But a diamond with a well-cut grade will also look good as it has high brilliance and sparkle. 

A 1-carat diamond with H color grade and VS2 clarity with excellent cut grades will be more expensive compared to a 1-carat diamond with H color grade and VS2 clarity but with good cut grades.

Final Thoughts

Whenever you intend to purchase diamond jewelry, it’s important to ask about the carat weight of the central stone. The central stone is the most visible and should have a high carat weight. 

Moreover, the central stone should have superior color, cut quality, and clarity grades than the smaller diamonds surrounding it. However, once you have decided on the center ring’s carat weight, cut, color, and clarity, you can use the CTTW to compare rings that have similar diamonds at the center.

Related articles:

What Is an Oval Diamond Bowtie?

What Is a Floating Diamond Wedding Band

GCAL vs. GIA – What Is the Best Diamond Certification?


James Allen Logo

James Allen is our most recommended online jeweler that guarantees a wonderful online shopping experience. You will find the most beautiful and best quality diamonds available for very competitive prices.

James Allen Diamond Rings