Professional Heart Diamond Size Chart & Conversion Tool
MM to CT / CT to MM Heart Shaped Diamond Size Comparison
There isn’t a lot of subtlety or hidden hints when it comes to the heart shaped diamond. It’s a clear and undeniable symbol of love that has been included in the world of diamond manufacturing in the early 1900’s. However, despite the clear and simple meaning behind of the heart cut, the ability to accurately measure it and get reliable ct to mm weight conversion requires more sophistication than meets the eye.
The good news is that most of the work has been done for you already, thanks to the following charts. Questions like what is the weight of a 3 Carat Heart Shaped Diamond in Millimetres? or How much is a 6.70 mm Heart Shape in Carats? All that and more is available, including guidelines for identifying and separating a great piece from a sub-par one.
How to Accurately Measure a Heart Shaped Diamond
A common mistake that even professionals can make when measuring a heart cut diamond is starting by measuring the horizontal width, followed by the vertical length and then dividing it. This unfortunately leads to a reversed order in the ratio, and can lead to confusion and inaccuracies.
As you can see by the image below, the ideal way to measure a heart shaped diamond is as followed, and how it is measured in GIA labs is as follows::
- Measure the Vertical Length.
- Measure of Horizontal Width.
- Divide the Length, with the Width.
Heart Shaped Diamond CT to MM / MM to Carat Conversion Charts
0.18-5.20 cts (Excellent Cut)
Copyright © AVA DIAMONDS
| HEART SHAPE CARAT WEIGHT | HEART SHAPE MM SIZE (RATIO of 0.95 - 1.02) EXCELLENT CUT |
|---|---|
| 0.18 - 0.21 ct. | 3.50 - 3.70 mm. |
| 0.23 - 0.26 ct. | 3.80 - 4.10 mm. |
| 0.27 - 0.29 ct. | 4.20 - 4.40 mm. |
| 0.30 - 0.38 ct. | 4.50 - 4.70 mm. |
| 0.40 - 0.45 ct. | 4.90 - 5.10 mm. |
| 0.50 - 0.57 ct. | 5.20 - 5.50 mm. |
| 0.60 - 0.65 ct. | 5.60 - 5.70 mm. |
| 0.70 - 0.75 ct. | 5.80 - 6.10 mm. |
| 0.80 - 0.85 ct. | 6.10 - 6.30 mm. |
| 0.90 - 0.95 ct. | 6.20 - 6.50 mm. |
| 1.00 - 1.10 ct. | 6.40 - 6.70 mm. |
| 1.20 - 1.30 ct. | 7.00 - 7.40 mm. |
| 1.50 - 1.60 ct. | 7.50 - 7.90 mm. |
| 1.70 - 1.80 ct. | 8.00 - 8.20 mm. |
| 2.00 - 2.20 ct. | 8.30 - 8.60 mm. |
| 2.40 - 2.60 ct. | 8.40 - 8.90 mm. |
| 2.70 - 2.85 ct. | 8.80 - 9.30 mm. |
| 3.00 - 3.20 ct. | 9.30 - 9.80 mm. |
| 3.40 - 3.60 ct. | 9.50 - 9.90 mm. |
| 4.00 - 4.20 ct. | 9.80 - 10.00 mm. |
| 4.40 - 4.60 ct. | 9.90 - 10.30mm. |
| 5.00 - 5.20 ct. | 10.50 - 11.10 mm. |
Ava Diamonds
0.17 - 2.20 cts (Good Cut)
Copyright © AVA DIAMONDS
| HEART SHAPE CARAT WEIGHT | HEART SHAPE MM SIZE (RATIO of 0.90 - 1.05) VERY GOOD CUT |
|---|---|
| 0.17 - 0.21 ct. | 3.30 - 3.70 mm. |
| 0.23 - 0.26 ct. | 3.60 - 3.90 mm. |
| 0.27 - 0.29 ct. | 4.00 - 4.30 mm. |
| 0.30 - 0.38 ct. | 4.20 - 4.60 mm. |
| 0.40 - 0.45 ct. | 4.60 - 4.90 mm. |
| 0.50 - 0.57 ct. | 4.90 - 5.30 mm. |
| 0.60 - 0.65 ct. | 5.30 - 5.70 mm. |
| 0.70 - 0.75 ct. | 5.50 - 5.80 mm. |
| 0.80 - 0.85 ct. | 5.80 - 6.00 mm. |
| 0.90 - 0.95 ct. | 5.90 - 6.30 mm. |
| 1.00 - 1.10 ct. | 6.10 - 6.50 mm. |
| 1.20 - 1.30 ct. | 6.60 - 7.00 mm. |
| 1.50 - 1.60 ct. | 7.10 - 8.50 mm. |
| 1.70 - 1.80 ct. | 5.00 - 5.30 mm. |
| 2.00 - 2.20 ct. | 7.90 - 8.20 mm. |
| 2.40 - 2.60 ct. | 8.00 - 8.50 mm. |
| 2.70 - 2.85 ct. | 8.40 - 9.00 mm |
| 3.00 - 3.20 ct. | 8.90 - 9.30 mm. |
| 3.40 - 3.60 ct. | 9.00 - 9.40 mm. |
| 4.00 - 4.20 ct. | 9.30 - 9.50 mm. |
| 4.40 - 4.60 ct. | 9.40 - 9.80 mm. |
| 5.00 - 5.20 ct. | 9.80 - 10.80 mm. |
Ava Diamonds
What are the Ideal Proportions of a Heart Cut Diamond?
You will find it difficult to find a shape that is more reliant on the quality of its symmetry than the Heart Shaped Diamond. After all, an asymmetrical shape, will simply not look like a convincing heart. Each half of the stone should be as equal as possible, as well as have the elegance of rounded shoulders that stem from it being a modified brilliant round cut.
Recommended Dpeth and Table for Heart Shapes
| EXCELLENT | VERY GOOD | GOOD | |
|---|---|---|---|
Table - % | 53% - 63% | 52% or 64% - 65% | 51% or 66% - 68% |
Depth - % | 58% - 62% | 56% - 57.9% or 62.1% - 66% | 53% - 55.9% or 66.1% - 71% |
Girdle | Very Thin to - | Slightly Thick | Very Thin to Thick |
Culet | None | Very Small | Small |
What is the Recommended Length to Width Ratio in Heart Cut Diamonds?
Generally speaking, when it comes to heart shapes, the closer you get to that sweet spot around the 1.00 or slightly below it, the btter chances you will have of having a superior stone. 1.00 of course. meaning that its length and width are near identical.
The lower you get from the sweet spot of 0.95 – 1.02 the more full, or chubby the stone will appear. On the other hand, the further you get from it, the more stretched of an appearance the shape will turn out to have.
| EXCELLENT | VERY GOOD | GOOD | |
|---|---|---|---|
| Length To Width Ratio | 0.95 - 1.02 | 0.89 - 0.94 or 1.03 - 1.05 | 0.83 - 0.87 or 1.06 - 1.10 |
