Emerald cut diamonds have an unmistakable elegance. Their long, stepped facets and rectangular shape offer a sophisticated sparkle that’s very different from the fiery brilliance of round diamonds. But when shopping for an emerald cut, size can be confusing - especially when trying to translate between millimeters (mm) and carats.
This guide breaks down everything you need to know about emerald cut diamond size charts, helping you choose the perfect stone with confidence.
Why Emerald Cut Sizing Can Be Tricky
Unlike round diamonds, where carat weight often matches common size expectations, emerald cuts can appear larger or smaller than their carat weight suggests. This happens because:
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Shape Ratio: Emerald cuts come in various length-to-width ratios (1.30–1.50 is most popular).
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Depth Percentage: Stones with shallower depths look larger face-up.
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Spread: The elongated table of an emerald cut can create the illusion of a bigger diamond.
That’s why mm measurements (actual physical dimensions) matter just as much as carats when evaluating an emerald cut.
Emerald Cut Diamond Size Chart (MM → Carat)
Below is an approximate chart for a standard length-to-width ratio of 1.40 and ideal depth percentages.
Note: Actual weights can vary slightly depending on individual stone proportions.
| Length × Width (mm) | Approx. Carat Weight |
|---|---|
| 5.00 × 3.50 mm | 0.40 ct |
| 5.50 × 3.80 mm | 0.50 ct |
| 6.00 × 4.00 mm | 0.70 ct |
| 6.50 × 4.50 mm | 0.90 ct |
| 7.00 × 5.00 mm | 1.00 ct |
| 7.50 × 5.20 mm | 1.25 ct |
| 8.00 × 5.50 mm | 1.50 ct |
| 8.50 × 5.80 mm | 1.75 ct |
| 9.00 × 6.00 mm | 2.00 ct |
| 9.50 × 6.50 mm | 2.50 ct |
| 10.00 × 7.00 mm | 3.00 ct |
| 11.00 × 7.50 mm | 4.00 ct |
| 12.00 × 8.00 mm | 5.00 ct |
Emerald Cut Diamond Size Chart (Carat → MM)
If you already know the carat weight and want to see the typical size in millimeters:
| Carat Weight | Typical Length × Width (mm) |
|---|---|
| 0.50 ct | 5.50 × 3.80 mm |
| 0.75 ct | 6.20 × 4.20 mm |
| 1.00 ct | 7.00 × 5.00 mm |
| 1.25 ct | 7.50 × 5.20 mm |
| 1.50 ct | 8.00 × 5.50 mm |
| 2.00 ct | 9.00 × 6.00 mm |
| 3.00 ct | 10.00 × 7.00 mm |
| 4.00 ct | 11.00 × 7.50 mm |
| 5.00 ct | 12.00 × 8.00 mm |
How to Use These Charts When Buying
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Check the MM Size in the Listing
Don’t just rely on the carat weight - always confirm the length and width in millimeters. -
Consider Your Ring Design
Certain settings, like halos or bezels, can make stones appear larger. -
Balance Size and Quality
A slightly smaller emerald cut with excellent clarity and color often looks more beautiful than a larger stone with visible inclusions. -
Account for Personal Preference
Some prefer a longer, more rectangular look (ratio 1.45–1.50), while others like a squarer shape (ratio ~1.30).
Common Questions About Emerald Cut Sizes
Q: Does an emerald cut look bigger than a round diamond?
Yes, emerald cuts have more surface area per carat, so they can appear larger face-up.
Q: What’s the best length-to-width ratio for emerald cuts?
Most buyers prefer 1.35–1.45 for balanced elegance, but it’s subjective.
Q: Is 1 carat big for an emerald cut diamond?
It’s considered a classic size, but due to the elongated shape, it can look larger than other cuts of the same weight.
Final Thoughts
When it comes to emerald cut diamonds, millimeters matter as much as carats. By understanding the relationship between carat weight and actual dimensions, you can confidently choose a stone that matches your vision - whether you’re after understated elegance or bold glamour.
