There are a number of factors that are important when you’re considering a diamond ring purchase, from the simple shape and appearance of a stone or band to details like the precise cut, clarity, or even various measurements. And when it comes to the latter areas, one of the factors that’s sometimes underplayed during the buying experience is known as diamond ratio.
Also called length-to-width ratio, this basic assessment of a diamond’s proportions is often a very important element in determining the final price of your ring. We’re happy to help with diamond ratio for all our engagement and wedding rings at AAA Jewelers – let’s go over what it means and how it’s calculated, plus break down the common ratios you’ll generally find in some of the more popular diamond cuts available today.
Diamond ratios are defined in millimeters, and the calculation for determining them is extremely simple: Find the length of the diamond, then divide it by the width. As a very simple example, a diamond that’s 11mm long and 8mm wide will have a ratio of 1.375, though some jewelers may choose to round up to tenths and label this 1.4 instead (the technically correct expression is 1.4:1, but the first number is often listed alone to save space).
Once you have this number, you have a general definition for the overall shape of the diamond. A perfect square diamond, for instance, will have a ratio of exactly 1.0, as it is evenly long and wide. Most other cuts, however, will have different and larger ratios – our next section will go over some standard ratios found in the kinds of cuts you’ll see at most jewelers today.