Updated 27 September 2026
A 1 carat round diamond measures about 6.5 mm across. A 2 carat is about 8.2 mm and a 3 carat about 9.4 mm. Carat is a measure of weight, not width, so doubling the carats does not double the size you see: a 2 carat diamond looks roughly a quarter wider than a 1 carat.
Round diamond size chart
| Carat | Diameter, about | Diamond price at Nivara |
|---|---|---|
| 0.25 ct | 4.1 mm | ₹12,500 |
| 0.50 ct | 5.2 mm | ₹25,000 |
| 0.75 ct | 5.8 mm | ₹37,500 |
| 1.00 ct | 6.5 mm | ₹50,000 |
| 1.50 ct | 7.4 mm | ₹75,000 |
| 2.00 ct | 8.2 mm | ₹1,00,000 |
| 2.50 ct | 8.8 mm | ₹1,25,000 |
| 3.00 ct | 9.4 mm | ₹1,50,000 |
Diameters are for a well cut round brilliant and vary slightly with cut proportions. Prices are for the diamond alone, VVS clarity and E colour; the gold and setting are added depending on the design.
Why a 2 carat diamond does not look twice as big
Carat measures weight. A diamond's weight sits in three dimensions, but you see it in two: the width across the top. So when the weight doubles, the width grows by only about a quarter. A 1 carat round is about 6.5 mm across and a 2 carat about 8.2 mm. It is worth knowing before you choose between two neighbouring sizes.
How big will it look on the hand?
An average woman's ring finger is about 16 mm across. On it, a 0.50 carat round covers about a third of the width, a 1 carat a little more than a third, a 2 carat about half and a 3 carat more than half. Slimmer fingers make the same diamond look larger. The surest test is to try a few sizes on at a private viewing.
Does cut change the size?
Yes. A diamond cut too deep hides some of its weight underneath and looks smaller face up than its carat suggests. An ideal cut spreads the weight correctly, so the diamond shows its full width and returns the most light. Every Nivara diamond is ideal cut, VVS clarity and E colour, and IGI certified.
Other shapes, other sizes
Elongated shapes carry their weight across a longer outline, so an oval, pear or marquise looks larger than a round of the same carat. For exact millimetre sizes by shape, see our guides to oval, pear, princess, cushion, emerald, radiant, marquise, asscher, heart diamonds.
Round solitaires from our collection
Prices are for 14k gold and move with the gold rate.
Amora minimal solitaire, from around ₹74,000. A single 1.00 carat round diamond, held between the ends of a clean gold band.
Amara split shank solitaire, from around ₹1,52,000. A single 1.59 carat round diamond on a split gold band.
See all round solitaires, and what a 1 carat lab grown diamond costs in India.
Every piece in our lab grown diamond jewellery is set with IGI certified diamonds in 14K or 18K BIS hallmarked gold.
What comes with every piece
- One diamond standard, whatever the budget: VVS clarity, E colour, ideal cut.
- IGI certification, and on solitaires the report number laser inscribed on the stone, so the paper and the diamond are one.
- 14k or 18k BIS hallmarked gold.
- A lifetime exchange at 100% of the current gold and diamond value, and a lifetime buyback at 100% gold and 85% diamond value.
- Lifetime polishing, cleaning and prong tightening, for as long as the piece is worn.
See the sizes side by side
A chart helps; seeing three carats next to each other on your own hand settles it. Book a private viewing at our showrooms in Hyderabad, Bangalore, Indore or Ahmedabad. Anywhere else in India or abroad, book a video consultation; we ship to 28 countries.
Frequently asked questions
What size is a 1 carat diamond in mm?
A well cut 1 carat round diamond measures about 6.5 mm across. The exact figure depends on the cut proportions: a stone cut deep carries more weight below the surface and looks slightly smaller face up, while an ideal cut shows its full width.
How big is a 2 carat diamond compared with a 1 carat?
A 2 carat round diamond measures about 8.2 mm across, against about 6.5 mm for a 1 carat. It weighs twice as much but looks only about a quarter wider, because the extra weight is spread through the depth of the stone as well as its width.
How big is a 3 carat diamond?
A 3 carat round diamond measures about 9.4 mm across. On an average woman's ring finger, about 16 mm wide, it covers a little more than half the width. At Nivara, a 3 carat VVS E diamond is ₹1,50,000 before the gold and setting.
How much does a 1 carat lab grown diamond cost?
At Nivara, every diamond is priced at ₹50,000 per carat for VVS clarity and E colour, so a 1 carat diamond is ₹50,000 before the gold and setting are added. The same rate applies at every size, which makes it easy to compare carats.
Does the shape change how big a carat looks?
Yes. Elongated shapes such as oval, pear and marquise spread their weight across a longer outline, so they look larger face up than a round diamond of the same carat. Our shape by shape size guides give the millimetre sizes for each.
