Reading Diamond Certs :: Table %

Table % is the ratio of the table width as compared to the total width (or girdle diameter) of the diamond.


For rounds, the largest diameter is used. For fancies, the smallest diameter (width as opposed to length) is used.

For example, if the table measures 5.7 mm, and the total diameter of the diamond measures 10.0 mm, then the table percentage is 57%.

It is important to note that the trend toward smaller table percentages is a very recent phenomenon. Until the last 10 years or so, most people preferred a slightly larger table because it added width to the stone without sacrificing brilliance and a small bit of fire. Today, the trend toward “perfection” is creating a great demand for diamonds that are cut to so-called “ideal” proportions, increasing the price for Ideal Cut diamonds.

Actually, perfect proportions are not possible because perfect proportions vary for each individual diamond — depending on the nature of the rough material and where the diamond is mined. Also, GIA has found in its research of millions of diamond proportion sets, that there are many configurations that produce optimum beauty in a diamond.

Each diamond has its own unique properties. Stones from four different mines can be cut to the exact same proportions but look very different. The ideal proportions for one diamond will not be the same for another. The value of Ideal Cuts should be considered carefully. It is true that good proportions make an enormous difference in the fire and brilliance of a diamond, but it is not true that all diamonds will look the same when cut to those proportions.

We recommend choosing a diamond that appeals to you, and do not let anyone tell you what looks better. They can only express their personal taste, which might not be the same as yours. Always buy what you like.

That said, the ranges commonly considered best for each shape vary slightly. We will give only the basic dimensions for rounds here. Dimensions for other shapes are beyond the scope of this brief report. However, for the most part, fancies also follow the same guidelines given below. The exceptions to this rule are princess cuts, radiants, and emeralds, for which you should allow up to 75-80% for acceptable ranges (in our opinion).

  • Ideal = 53 – 58%
  • Excellent = 58.1 – 60%
  • Good = 60.1 – 64%
  • Fair = 64 – 70%
  • Poor = over 70%

Please Note:

Discounts for stones outside of these limits are too difficult to explain here. If you want to learn how to calculate a price for any diamond you want, please see my easy, fast, step-by-step Diamond Pricing Tutorial page.

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