What Is CTTW For Diamonds?

by Ultimate Jewelry Guide
What Is A CTTW Diamond?

The world of diamonds is full of sparkle, and choosing the right one from a plethora of options requires proper understanding and knowledge of the various terms used by jewellers and diamond traders in order to make a smart and informed purchase.

One such abbreviation which you shall often encounter is “CTTW diamond”.

Though this may sound like mathematical jargon, these letters mean ‘total carat weight’.

The carat weight of a single diamond and the total carat weight of a diamond ring are two very different numbers, which can be confusing for first-time buyers.

Understanding the distinction between Ct. and Cttw is crucial as it will allow you to understand exactly where your money is being spent. 

So what exactly is Cttw, how it differs from Ct. and why is it important for you?

Check out this blog to know more and feel confident while you purchase diamonds. 

What Are Carats In Diamonds?

Carat is the international unit used to measure a diamond’s weight. It is one of the 4Cs of diamond quality, used to determine a diamond’s value. 

The other Cs are color, clarity and cut.

Carat weight is abbreviated at ‘ct.’ and is placed after the numeric value and expressed up to two or three decimal places. Diamond weight can also be abbreviated as ‘DW’.

One carat is the equivalent to 200 milligrams or 0.2 grams. 

Alternatively, 5 carats = 1 grams. A carat is subdivided into 100 equal parts called ‘points.’ So, ½ carat = 50 points, and 1 carat = 100 points.

The carat weight of a diamond refers to its weight rather than the size.

Two stones can be identical in weight but differ greatly in terms of appearance.

A diamond of a single carat can range in diameter from 5.60mm to 6.60mm depending on its cut grade. Marquese, oval, pear shaped diamonds tend to look larger than round diamond of the same carat weight.

What Does CTTW Mean?

CTTW stands for ‘carat total weight’ or ‘total carats weight’. The total diamond weight can be also abbreviated as ‘TDW’.

It is a metric that’s used to measure the total weight of all the diamonds encrusted in a specific piece of jewelry such as a ring, bracelet, earrings, etc. This will include the center stone as well as any accents, or pave. 

CTTW is used to weigh the weight of diamonds solely (natural/ lab grown). It does not take into account any other gems on the jewelry such as emerald, ruby, sapphire, etc.

What Is The Difference Between CT & CTTW?

CTTW differs from carat in that, carat is used to show the weight of a single diamond on its own, however CTTW is used for the total carat weight of all diamonds. It is the weight summation of all the diamonds collectively found in the piece of jewelry.

Put simply, ‘Carat weight’ refers to the weight of a single diamond. ‘Total carat weight’ refers to the sum total of multiple diamonds.


  • A three stone diamond ring marked 2 CTTW is one that has 1 ct. center diamond and two 0.5 carat side stones, that make up 2 carats in total.
  • On the flip side, a diamond ring labelled 2 carats CW is actually a ring with a single 2 carats diamond.
  • Likewise, a bracelet with twenty 0.20 carat diamonds may be labelled as a 4 Cttw.
  • Many engagement rings only contain one center diamond, called as solitaire. As a result, the ring’s total carat weight (CTTW) will be the same as the carat weight of the center stone.

How To Find Your Diamond’s CTTW

The diamond trade uses sophisticated tools for weighing and measuring diamonds, and accuracy is essential. Diamond carat weight is measured by sensitive instruments, i.e, Electronic micro-balance scale. These scales are equally useful for weighing individual stones and large parcels.  To calculate the total carat weight, carat weight of all the diamonds in the piece of jewelry are simply added together.

How To Use CTTW To Buy Diamonds

Whenever you buy a piece of diamond jewelry, ask for the total carat weight and the carats. These numbers are an important consideration because they:

  • Help determine a diamond’s price and reflects its rarity.
  • Help state the total number of stones on the ring, or their sizes.
  • Gauge the total value of the jewellery item.
  • Help to compare different jewelry items having the same cttw.
  • Determine which piece of jewelry contains more diamond (in terms of weight) and which would be a better deal in terms of price.

How CTTW Influences The Value Of A Diamond

Carat weight and total carat weight have a significant impact on the price of diamond jewelry. When looking at loose diamonds, the price increases exponentially with the carat weight.

The reason for this is simple. Large diamonds are significantly rarer than smaller diamonds and as a result, they command higher prices.

However, this is not the case for CTTW. As the given value is a total, there is no exponential relationship between carat total weight and price.

The chief driver of price is the size of the center diamond, along with the size of the accent stones, assuming all are the same quality.

While a ring with a large total carat weight can look impressive, it’s the weight of the center stone which is usually the biggest factor in determining a ring’s value.  If the Cttw is split between two or more diamonds, that jewelry piece would cost less than if the piece only had one diamond.

Rings with fewer, larger stones are much more valuable than those with many smaller diamonds at the same cttw.

For example, the cost of a ring with 10 diamonds weighing 0.10cts each (i.e. 1 Cttw) is less than a 1 carat diamond solitaire ring, even though the total carat weight is the same.

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