Diamond Size Chart
Round Diamond Size Chart
The round diamond is the most popular cut, loved for its sparkle and symmetry. But carat weight doesn’t always tell you how big it looks.
Average Round Diamond Sizes
- 0.50 carat ≈ 5.1 mm
- 1.00 carat ≈ 6.4–6.5 mm
- 2.00 carat ≈ 8.1–8.2 mm
Because round diamonds are cut deep to maximize brilliance, they may look slightly smaller than fancy shapes.
Tip: If you want the diamond to look larger, choose a thinner band or a halo setting.
Select a diamond shape.
| MM Size | Carat Weight |
|---|---|
| 0.8 mm | 0.0025 ct |
| 1 mm | 0.005 ct |
| 1.1 mm | 0.0067 ct |
| 1.2 mm | 0.009 ct |
| 1.25 mm | 0.01 ct |
| 1.3 mm | 0.01 ct |
| 1.5 mm | 0.015 ct |
| 1.75 mm | 0.02 ct |
| 1.8 mm | 0.025 ct |
| 2 mm | 0.03 ct |
| 2.2 mm | 0.04 ct |
| 2.5 mm | 0.06 ct |
| 2.75 mm | 0.08 ct |
| 3 mm | 0.10 ct |
| 3.25 mm | 0.14 ct |
| 3.5 mm | 0.17 ct |
| 3.75 mm | 0.21 ct |
| 4 mm | 0.25 ct |
| MM Size | Carat Weight |
|---|---|
| 4.25 mm | 0.28 ct |
| 4.5 mm | 0.36 ct |
| 4.75 mm | 0.44 ct |
| 5 mm | 0.50 ct |
| 5.25 mm | 0.56 ct |
| 5.5 mm | 0.66 ct |
| 5.75 mm | 0.75 ct |
| 6 mm | 0.84 ct |
| 6.25 mm | 0.93 ct |
| 6.5 mm | 1.00 ct |
| 6.8 mm | 1.25 ct |
| 7 mm | 1.30 ct |
| 7.3 mm | 1.50 ct |
| 7.5 mm | 1.67 ct |
| 7.75 mm | 1.75 ct |
| 8 mm | 2.00 ct |
| 8.25 mm | 2.11 ct |
| 8.5 mm | 2.43 ct |
| 8.7 mm | 2.50 ct |
| MM Size | Carat Weight |
|---|---|
| 9 mm | 2.75 ct |
| 9.1 mm | 3.00 ct |
| 9.5 mm | 3.35 ct |
| 9.75 mm | 3.50 ct |
| 10 mm | 3.87 ct |
| 10.25 mm | 4.00 ct |
| 10.5 mm | 4.41 ct |
| 10.75 mm | 4.50 ct |
| 11 mm | 5.00 ct |
| 11.25 mm | 5.49 ct |
| 11.5 mm | 5.85 ct |
| 12 mm | 6.84 ct |
| 12.25 mm | 7.26 ct |
| 12.5 mm | 7.36 ct |
| 12.75 mm | 7.52 ct |
| 13 mm | 8.51 ct |
| 13.5 mm | 9.53 ct |
| 14 mm | 10.49 ct |
| 15 mm | 12.89 ct |
| 16 mm | 16.06 ct |
Frequently Asked Questions
Why are round diamonds considered the most popular shape?
Round diamonds are the most sought-after because of their unmatched brilliance and timeless look. Their symmetrical cut maximizes light reflection, making them sparkle more than any other shape.
How do I use the round diamond size chart?
The chart shows millimeter dimensions for each carat weight, helping you visualize how large your diamond will appear when set in a ring.
Do round diamonds look bigger than fancy shapes of the same carat?
Yes, round cuts often appear slightly larger due to their shallower depth and wider face-up area compared to deeper cuts like cushion or princess shapes.
What’s the ideal depth and table percentage for round diamonds?
A depth of 59–62.5% and a table between 54–58% are ideal for maximizing brilliance and fire.
What diamond size looks best on average finger sizes?
Round diamonds between 1.0 and 1.5 carats suit most hand sizes, offering the perfect balance between sparkle and comfort.
How does carat size affect the price of round diamonds?
Round cuts are the most expensive per carat since they lose the most rough diamond during cutting and are in the highest demand.
Do round diamonds hide inclusions better than other shapes?
Yes, their brilliant facet pattern helps disguise small imperfections better than step-cut diamonds like emerald or Asscher cuts.
What setting makes a round diamond appear larger?
Halo, bezel, or thin-band solitaire settings can enhance the stone’s presence and make it look bigger on the hand.
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