Diamond Carat Size and Engagement Rings

Half Carat, One Carat, Two Carat - Engagement Rings?

This section of our Engagement Rings Buyers Guide, explains Diamond Carat Size.

One of the great things about buying an engagement ring from us online, is that you get to choose the carat size of the diamond you would like. This page covers a number of important factors relating to diamond carat size:

There are a number of other pages in this guide that relate to diamond quality. We recommend you read the Diamond Clarity, Diamond Colour and Diamond Clarity pages. If you need further assistance, please enquire.

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How does Diamond Carat Weight Relate to Size?

The weight of a diamond is measured in carats. One carat is 200 milligrams. The table below shows how the weight of a diamond approximately relates to its size.

diamond carat size chart for engagement rings
Please note, that the chart above is only applicable to the round diamond shape.

Important: CTW (Carat Total Weight) is not CT (Carat Weight)

Take care not to be confused by CTW and CT.

  • CTW refers to the total weight of all diamonds used in an engagement ring.
  • CT refers to the carat weight of a single diamond, usually the main centre diamond.
  • Large diamonds are rare and therefore cost a lot.
  • Small diamonds are plentiful and are relatively much cheaper.

One carat total weight (CTW) of small diamonds is therefore not worth the same as a single one carat diamond (CT).

Multi-stone engagement rings are really nice, just be sure to check both the CT and the CTW when comparing prices!

How does Carat Weight Affect Price?

The diamond carat weight of the main diamond(s) in an engagement ring has a huge influence on the price of the engagement ring. Of course gold and platinum are precious metals, so they too have an impact on the price, but the diamond is the most expensive part.

Diamonds are traded as a commodity on diamond bourses (a bit like a stock exchange, but for diamonds). There shouldn't be a great deal of difference in the price you have to pay for a diamond from one jeweller to the next. However, high street jewellers have large overheads associated with rent, rates, staff, display cases, stock etc, and as a result you typically pay a lot more than you would if you buy online. In fact the difference can be 50%-100% more.

Many people want to try an engagement ring on before buying and so Internet purchasing is not for them. They are typically happier to pay more, in order to have the high street service. Others perhaps: want to keep the purchase a surprise; or are used to buying online; or want to get much better value for money; and are reassured to know that we can send very high quality large pictures of a ring, and ultimately we offer a 100% refund, 7-day return policy.

What Other Factors Should I Consider When Choosing a Diamond for My Engagement Ring?

Clearly the most important factor in purchasing a diamond engagement ring is whether you like the ring. You should additionally consider: how suitable a ring is to your partner's lifestyle and personality and of course the other diamond factors that relate to quality:

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