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CTTW & TW Diamond Meaning

cttw, ctw and tw are probably among the most dangerous letters in the diamond industry for unfamiliar buyers.

What is CTW and TW? What you MUST know about Total Carat Weight vs. Carat Weight

CTW…CT…TDW…CW…TW of a diamond, What is the meaning of all of those abbreviations anyway?

When it comes to carat weight it is customary to use ct as shortage for carat and cts for carats. So the short answer is that CTTW stands for Carat (CT) and Total Weight (TW) of a diamond or diamonds. And here are all of the abbreviations related to diamond/s weight:

  Diamond Weight Abbreviations Explained

Abbreviations Meaning
CT Carat
CTS Carats
CTW Carat Weight
CTTW Carat/s Total Weight
TDW Total Diamond/s Weight
TW Diamonds Total Weight of Diamonds

Learn the difference between carat weight and total carat weight and how to decipher the lingo of diamond and jewelry experts for a smart and informed diamond ring purchase. And to put it in numbers:

7.21ctw yellow diamond ring
3.54ctw yellow diamond ring

Why the first ring with 7.24 carats of yellow diamonds costs half from the second ring that has a total carat weight of 3.54 carats? (both rings are from our collection of yellow diamond rings)

How to Interpret Diamond Weight Shortened Jargon?

When shopping fo a diamond engagment ring, you will encounter two main terms - carat weight and total carat weight. It's surprising how two so very similar phrases can be so dangerously different. By dangerous I mean to your pocket...

What is Carat Weight?

A Carat is the universally accepted unit of measurement for diamond weight. One carat is equal to 200 milligrams (0.20 grams), alternatively you can say that 5 carats are the equivalent to one gram. And this is the last time you'll hear of grams when it comes to diamonds.

0.01 carat is also referred to as carat point. Meaning that 50 points are half a carat.

The word carat originates from the historic method of weighing diamonds with carob seeds. Before modern weighing machines were developed, diamonds were weighed on balance scales where the unknown weight of an object was measured by counting the number of unit weights needed to counterbalance it. Small enough and considered to be of uniform weight, carob seeds were used as weight units for diamonds.

Today, diamond carat weight is measured by sensitive instruments and is the most important factor when determining the price of the diamond. It is one of the 4 C's of diamonds.

Carat weight has generally come to represent the size of a diamond. It is commonly accepted that as diamond carat weight increases, so does the size of the stone. BUT this is NOT 100% TRUE! Weight is a measurement of mass (how much matter is in a given item) whereas size reflects the volume (the amount of space the item takes up).

An easier to understand analogy would be that a heavier person, weighing 160 pounds, wouldn't necessarily look bigger than a person weighing 155 pounds or even 150.

It reminds me a bit of the famous riddle... (or joke):

What weights more, a pound of feathers or a pound of bricks?

Of course, they both weigh the same, a pound, but the size of the two is very different. Because the bricks are made of denser matter, they take up less space than the feathers at the same weight and are smaller in size.

Similarly, the size of an object is also influenced by the shape it takes. Longer shapes seem larger than flatter ones. Therefore, marquise, oval, and pear diamonds tend to look larger than round diamonds of the same carat weight.


What is Total Carat Weight?

Total carat weight refers to the sum total weight of all diamonds set in a jewelry item. To calculate the total carat weight, simply add together the carat weight of all the diamonds in the piece.


“carat weight” refers to the weight of one given stone

“total carat weight” refers to the sum total of multiple stones.

For example, a three stone ring that has a 1 CT diamond centerstone and two ½ carat sidestones is a 2 CTW ring.

CTW & CTTW - Carat Weight and Buying a Diamond Ring

Understanding the significance of CTW & CTTW is critical when shopping for a diamond ring. If you are in the market for an engagement ring with one diamond, also known as a solitaire ring, its CTW will be the same as the carat weight of that one diamond. Other ring styles with multiple stones such as halo, sidestone, or threestone can be more tricky when considering CTW. Let’s look at some important points to remember when shopping for these rings.

Quantity vs. Quality

Because CTW represents the sum total of multiple diamonds, rings with the same CTW may differ greatly in how many diamonds they hold. A ring with a few larger diamonds might have the same CTW as a ring with many smaller diamonds.

The most extreme example is eternity rings. The total weight of diamonds in them (i.e. TW Diamonds) is quite significant whereas the weight of each diamond is negligible.

The first is a 2.00 ctw eternity ring valued at $4,000 and the second is a 2.00 ct solitaire ring valued at $19,000. Both rings can be found at James Allen

Taking advantage of many smaller stones to inflate the CTW of a diamond ring is a common marketing technique used to make rings appear more desirable.

Effects on Ring Price and Value

Whether the CTW of a ring reflects a few larger stones or many smaller stones will influence the price of the ring significantly. To understand the effect that individual diamond carat weights have on the overall price of a ring, it is important to remember how diamonds are priced. Bigger diamonds are rarer in nature, and therefore, the price of diamonds rise exponentially as size increases. Meaning, a 1 ct diamond will be more than twice the price of a ½ carat diamond.

Recommended Readings: Diamond Prices - How to Get the Value without the Cost?

This reality of pricing means that two rings with the same CTW will differ in value depending on the size of the stones that make up the ring. Rings of the same CTW consisting of many small stones will hold less value than those that hold fewer but larger stones.

Additionally, smaller ring sidestones that serve to boost CTW are usually NOT GRADED, and therefore are of lesser quality and less valuable.

You would think that ring prices would reflect these differences in value, BUT this is NOT always true. In fact, rings with many smaller sidestones often cost more than a ring with a few larger sidestones of the same CTW! This may be due to the extra production work and time required when setting many small stones as opposed to a few larger diamonds, or simply because jewelers know the average customer is none the wiser. Either way, PRICE DOES NOT ALWAYS REFLECT VALUE!

Making the Most of Carat Weight and CCTW

Keeping in mind how the quantity and value of diamonds varies when considering CTW, here are a few ways to make the most of your diamond ring purchase:

Remember that carat weight reflects the mass of the diamond and not necessarily the size? When looking for a diamond ring, remember that longer shapes seem larger than flatter ones to the human eye. Marquise, oval, and pear diamonds tend to look bigger than round diamonds of the same carat weight and are often priced lower than round cut diamonds due to lesser popularity.

When considering rings with sidestones, take note of how they are placed along the ring. According to the Law of proximity, one of 6 Gestalt laws of perception, "objects that are close to one another appear to form groups". This means that sidestones grouped closely together seem smaller than the same number of sidestones that are spread out over more area of the ring.

For example, given identical center stones, which ring do you think has more diamonds? And which costs more?

Halo Diamond Ring with 0.34cctw melee diamonds
0.10cctw Milgrain Diamond Ring

Both rings are taken from Blue Nile's Engagement Ring Collection

At first glance it looks like the second ring with the side-stones setting has more diamonds than ring one, more sparkle. BUT, the first ring actually has more diamonds (quantity wise) and they are also bigger diamonds than the ones in the second ring!

The first, the halo Ring, 12 surrounding diamonds weighing 0.34 carats while the second ring only has 10 diamonds weighing 0.10 carats total. This illusion is due to the fact that in ring 1, the halo design concentrates the diamonds close together, and we perceive them all as one object, while in ring 2, the sidestones are spread out along the band, making them seem more than they are.

On top of that, the second ring has what is called a milgrain decoration. Which ads sparkle to it making it look like there are also more small diamonds in the setting.

To conclude - as in many other cases its not about the quantity but rather the quality. Bigger diamonds are rarer and considered of higher quality than smaller diamonds. Make sure you are getting what you paid for, the cost of a ring with 10 diamonds weighint 0.10cts each (i.e. 1.00ctw) is far less than a ring with one 1.00 carat diamond.

As always, if you have any further questions, please do not hesitate to contact us!