What You Need to Know About CTTW, or Carat Total Weight, Before Buying a Ring

What You Need to Know About CTTW, or Carat Total Weight, Before Buying a Ring

When it comes to finding the perfect diamond engagement ring, the four C's — cut, color, clarity and carat — are your BFFs. You should do some thinking about your priorities, and which of the C's should be allotted VIP status in your budget. Carat is a good place to start, but it's important to know that it can be a slightly complicated calculation. You should get to know CTTW, because it will dictate the effect of the ring you select.

What is CTTW and How is it Different from Carat?

Remember that carat is a measure of weight, not size. CTTW stands for carat (CT) and total weight (TW). In a piece of jewelry that has more than one diamond, it's the weight of all the diamonds, added together.

CTTW - Comparison

What You Need to Understand About CTTW

    • Yes, it's only for diamonds.

CTTW refers to the weights of the diamonds in a ring. If you're interested in, say, a sapphire and diamond engagement ring, the CTTW doesn't consider the sapphires. Important to note: Companies that use lab-made diamonds still use CTTW, so it isn't necessarily a measure of just real diamonds.

    • CTTW doesn't tell you much about price.

Two rings can have identical CTTW numbers, but their prices can be drastically different. It depends on how much of the CTTW comes from center stone and how much from the accent stones. For example: A ring may have six small stones and a 1 carat center stone, yet cost much less than a ring than has a 1 carat diamond in the center and two larger accent stones. Remember: Diamonds are priced exponentially, not linearly. Larger stones are rarer, so they cost disproportionately more.

    • CTTW is a total of both earrings.

If you're buying earrings, divide the CTTW by two to find out the size of the stone(s) on each individual earring.

You can always ask for a breakdown of all the stones in a piece, if it isn't listed. Contact our gemological team.

Have More Questions?

Ready to tackle the four C's, CTTW and all the other glorious acronyms in one of the most important purchases you'll ever make? With Clarity has expert gemologists on staff who are experienced in helping couples find the perfect ring for any budget. Contact one today, or browse our large selection of ethically sourced diamond engagement rings.

Contact us by phone at 1(844)-234-6463 or email at service@withclarity.com. Our Live Chat is available during business hours Monday - Friday, 10 AM - 5:30 PM ET.


What does cttw mean?

CTTW stands for carat (CT) and total weight (TW). In a piece of jewelry that has more than one diamond, CTTW refers to the weight of all the diamonds added together.

Are diamonds measured in cttw?

The weight of a single diamond is measured in carat weight, but if there are more diamonds in the entire piece of jewelry then their weight will be measured in cctw.

Is metal measured in cttw?

No, metal is not measured in cttw. Cttw refers to the total weight of diamonds in a piece of jewelry. When it comes to metal, for example gold, the weight is measured in troy ounces. 'Caratage' is the term used to measure the purity of gold, when it is alloyed with other metals.

Are lab grown diamonds measured in cttw?

Diamonds, including lab diamonds, are measured or weighed in metric carats, where one carat is equal to 0.2 grams.
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