Oval Cut Diamonds | Guide, Proportions, L/W Ratio

Similar to other elegant diamond shapes, preferences for an oval cut diamond also vary based on its length-to-width ratios. A traditional oval cut diamond typically features a length-to-width ratio of 1.50 or falls within the approximate range of 1.36 to 1.60. This range elongates the outline sufficiently to distinguish it from a round-cut diamond. However, the shape can resemble a marquise cut if the elongation becomes excessive.

Ideal Length-to-Width Ratio of 1.45

The "bow-tie effect" is noticeable in nearly all oval, marquise, and pear-cut diamonds. Given its significance in evaluating oval cut diamonds, we invite buyers to explore our dedicated article on the impact of the bow-tie effect on fancy-shape diamonds for a deeper understanding. In our view, a subtle "bow-tie effect" enhances the appeal of an oval-cut diamond. Conversely, avoiding a pronounced "bow-tie effect" is advisable, as it suggests suboptimal diamond cutting.

To meticulously compare distinct diamonds, utilize advanced tools like this video technology, featuring 40X magnification. It can aid in evaluating the influence of an oval cut diamond's proportions on its overall brilliance. Furthermore, it is a valuable resource for determining the ideal length-to-width ratio that aligns with your preferences.

The following proportions serve as a general guideline when evaluating the cut quality of an oval cut diamond.

A traditional oval diamond typically has a length-to-width ratio of 1.50. Nevertheless, determining the optimal length-to-width ratio depends on individual preference and taste. From our perspective, we hold an affinity for ratios within the range of 1.40 to 1.55. 

As illustrated below in the section on how to read a GIA grading report, these reports provide precise measurements that facilitate the calculation of the length-to-width ratio for an oval cut diamond (achieved by dividing the length by the width).

When comparing the following three distinct oval cutting styles, we recommend the one with facets resembling the middle image below (please look at the GIA report for its specific cutting style).

The above cutting styles on the left and right represent older iterations, while the one in the center illustrates the contemporary modified brilliant cut. Featuring 57 to 58 facets, akin to a round brilliant cut, this modern style offers optimal brilliance, scintillation, and fire.

Color plays a pivotal role when evaluating oval cut diamonds. After cut, color should be prioritized to maximize a diamond's brilliance. Consider a D to F color range for optimal results unless budget constraints dictate otherwise. Nevertheless, G color also proves commendable, offering a splendid appearance that closely aligns with colorless diamonds in terms of their visual allure.

If budget considerations are involved, H and I color present attractive options. Notably, these options come with a significantly lower price premium, making them appealing for those seeking both cost-effectiveness and visual appeal.

The accompanying table provides an informative reference for an in-depth examination of color when buying oval cut diamonds.

Choose an oval cut diamond that meets your standards for clarity. Each buyer has a distinct viewpoint concerning a diamond's clarity grade. While some aspire to a flawless gem, others find solace in minor inclusions, provided the diamond remains visually clean.

For dependable and accurate diamond clarity grading, reputable labs like GIA and AGS are benchmarks. Typically, most SI1 diamonds in the 1-1.3 carat range are perceivably free from inclusions to the naked eye. However, when considering diamonds in the 1.5 carat+ range, opting for a VS2 clarity grade is generally advisable.

Use the following chart as a general guideline when evaluating the clarity grades of oval cut diamonds depending on their carat weight:

In addition to the well-known 4Cs, buyers must be familiar with the following key aspects of an oval cut diamond grading report or certificate, as highlighted in the image below.

Watch HD Video of this Diamond.

Measurements: This is significant as it provides the buyer with information about the surface size of the diamond (indicating how large the diamond will appear in millimeters). It will also give you the length-to-width ratio by dividing the length by width (in the above case, it is 8.47/6.02=1.4).

Fluorescence: This should be regarded as the 5th C. Given that the color is D, avoiding fluorescence is the optimal choice in this example. However, medium blue fluorescence is not as concerning as strong blue fluorescence.

Comments: This section will display factors related to clarity and highlight whether a diamond has undergone clarity enhancement utilizing methods like laser drilling or color enhancement. Additionally, be attentive to comments such as "clarity grade based on clouds," which is a worrisome indicator within clarity grades of VS2 and below. The laser inscription of the report number on the girdle is positioned above the comments section, offering an optional service for added verification.

Proportions: This chart is the most crucial for assessing the cut of a diamond. Specifically, pay attention to the table percentage (60% in the example, excellent), depth percentage (62.4%, excellent), girdle (medium, excellent), and culet (none, excellent).

Clarity Characteristics: This section will indicate the types of inclusions and their respective locations. It can help buyers avoid diamonds with visible inclusions at the center. These details are also useful for correlating the report with the diamond, as these inclusions serve as the diamond's unique birthmarks.

Below, we have provided four primary scenarios of how our clients have frequently prioritized the 4Cs during their search and shopping process. These scenarios are designed to aid potential buyers in establishing a suitable strategy when buying oval cut diamonds.

Scenario 1: Quality-Driven Approach

Clients in this category prioritize top-tier quality. They opt for the finest combination of 4Cs within each carat weight range. Their selection for diamonds above 1 carat includes D and E color, VS1+ clarity, excellent cut, no fluorescence, and GIA or AGS certification. This emphasis on quality ensures buyers acquire an investment-grade diamond.

Scenario 2: Balancing Quality and Size

In this scenario, clients seek a balance between quality and size. While still valuing quality, they are willing to make slight concessions to secure a larger diamond. Their choice centers around a 1.5 carat diamond with SI1/VS2 clarity, F/G color, very good to excellent cut, medium blue fluorescence at most, and GIA or AGS certification. These diamonds are relatively high quality and accommodate a larger size.

Scenario 3: Emphasizing Size with Moderate Compromises

Buyers here prioritize size while moderately compromising on the 3Cs. They prioritize a larger stone as long as it remains visually clean and displays ample brilliance. They prefer a 2 carat diamond with I/J color, SI1/SI2 clarity, strong blue fluorescence at most, very good to ideal proportions, and GIA or AGS certification. An adequate understanding of clarity assessment is essential, particularly in avoiding visible inclusions like large black crystals.

Scenario 4: Maximized 3Cs with Color Compromise

Clients in this scenario are willing to compromise heavily on one "C" to elevate the importance of the 3Cs. Their focus shifts to clarity and cut quality while compromising on color. This choice maintains fire and brilliance while resulting in a slightly warmer diamond. An optimal choice entails a VVS2 clarity, L color, medium to strong blue fluorescence, and ideal proportions. Notably, certifications from IGI or HRD grading labs are also viable, given their consistency in grading diamonds with lower color grades, even if they might be less strict than GIA in grading high-quality stones.

Use the above scenarios to narrow your selection criteria according to your preferences and priorities.

Although a universal formula for determining oval cut diamond prices is yet to be developed, the prices below represent our most informed approximation for competitive retail prices of oval cut diamonds with a GIA grading report, ideal proportions, and no fluorescence.

• 1 Carat, D-E Color, FL-VVS ($8,400-9,800), G-H Color, VS1-VS2 Clarity ($4,400-6,600).
• 1.5 Carats, D-E Color, FL-VVS ($18,500-23,000), G-H Color, VS1-VS2 Clarity ($92,00-12,500)
• 2 Carats, D-E Color, FL-VVS ($32,000-39,000), G-H Color, VS1-VS2 Clarity ($20,000-25,000)
• 2.5 Carats, D-E Color, FL-VVS ($52,000-64,000), G-H Color, VS1-VS2 Clarity ($33,000-$42,000)
• 3 Carats, D-E Color, FL-VVS ($85,000-110,000), G-H Color, VS1-VS2 Clarity ($43,000-56,000)

Top Oval Shaped Engagement Rings

See the following suggested carat weight, cut, color, and clarity of oval cut diamonds for people on a tight budget.

Excellent Choice

• At least 1.2 Carat in Weight
• Very Good to Excellent Polish and Symmetry
• G or above in color
• SI1 or above in clarity
• No Fluorescence
• Length/width ratios: 1.36 - 1.58

Very Good Choice

• At least 1 Carat in Weight
• Good to Excellent Polish and Symmetry
• H or above in Color
• SI1 or above in Clarity
• None, faint or medium blue fluorescence
• Length/width ratios: 1.36 - 1.58

Good Choice

• At least 0.90 Carats in Weight
• Good to Very Good Polish and Symmetry
• I or above in Color
• SI1 or above in Clarity
• None, faint or medium blue fluorescence
• Length/width ratios: 1.36 - 1.58

Check our guide on lab-created diamonds as an alternative to natural diamonds for budget-conscious buyers.

Are oval cut diamonds popular?

Following round cut diamonds, oval diamonds have recently risen in popularity, claiming the position of one of the most sought-after shapes. They have gained traction among individuals who appreciate the appeal of round diamonds but are seeking a distinct and unique choice.

What about the size of oval cut diamonds compared to round cut diamonds?

Oval cut diamonds have a substantial surface area. Their elongated shape results in a larger surface area measured in millimeters compared to a round diamond

Do oval cut diamonds sparkle the same as round diamonds?

Because of modern cutting techniques, rounds are the king of sparkle and scintillation, but oval cut diamonds are the queen. They stand second in sparkle to round diamonds and have similar brilliant faceting that qualifies the diamond as a modified brilliant cut.

What about the bow-tie effect in oval cut diamonds?

The bow tie is a concern that can harm oval cut diamonds. Carefully review our bow-tie guide and discuss the bow-tie effect with the retailer before purchasing an oval-cut diamond. If a stone is cut poorly with uneven proportions, it will exhibit a significant bow tie—a clear indicator of a substandard cut.

What is the ideal length-to-width ratio for oval cut diamonds?

A range of 1.3 to 1.6 is considered favorable. The choice within this range hinges on how close to a round appearance you desire the stone to be. Any measurement falling between these values is suitable, though our preferred range is 1.4 to 1.55.

Check our loose diamonds page for recommendations on the best places to buy oval cut diamonds.