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
Heart Shaped Diamond on Hand
A heart shaped diamond truly comes alive once it rests on the finger. The classic design with its two rounded lobes at the top and gentle taper down to a soft point creates a romantic and playful look that feels personal and eye-catching.
The wider top portion provides good coverage across the finger while the tapered bottom keeps everything graceful and balanced. Brilliant faceting sends lively sparkles outward from the center cleft, producing a twinkling effect that moves beautifully as the hand shifts. Many people are pleasantly surprised by how substantial and meaningful a well proportioned heart cut looks in real life, often appearing larger and more striking than its carat weight suggests.
Many people love how it appears even larger and more dazzling in real life than the carat weight suggests, making it one of the most popular choices for engagement rings and statement jewelry.
The following image should aid you at visualizing how a 1ct Heart Cut Diamond would look like on your finger, or other weights you have in mind.
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 |