Why does a round cost more than an oval of the same carat?

Round brilliant wastes more of the diamond rough during cutting, and the demand is higher, so the per-carat price is typically 20–40% more.

How big does a 1ct round look?

A 1ct round is about 6.5mm across — a familiar, unmissable presence without being dramatic.

Round vs oval — which reads bigger?

An oval of the same carat weight reads roughly 15–20% bigger face-up because the shape stretches the outline.

Best setting for a round?

Solitaire is the classic; halo or hidden halo add sparkle and perceived size; pavé bands add finger-length sparkle without competing with the center.

Round brilliant, the one everyone starts with.

Is a round the right shape for me?

The most brilliant cut and the easiest to size in your head. See what a 1ct, 1.5ct, and 2ct round actually look like at true scale.

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What it actually looks like

Round brilliant is the shape most people picture when they hear the word diamond. Fifty-eight facets, more sparkle per carat than any other cut, and the most predictable look on the hand.

It's also the one shape where face-up size lines up almost exactly with carat weight. A 1ct round is about 6.5mm across. A 1.5ct is 7.5mm. A 2ct is 8mm. Easy to picture, easy to compare.

The tradeoff: round costs more per carat than any other shape. You're paying for both the cut precision and the fact that more rough diamond is wasted to produce it.

In this guide

Round carat-to-mm at true scale
Why round holds its value differently
Best settings for round: solitaire, halo, pavé
How round compares to oval and cushion

Round size, at true scale

1ct ≈ 6.5mm. 1.25ct ≈ 6.9mm. 1.5ct ≈ 7.4mm. 2ct ≈ 8.1mm. On a size-6 finger, a 1ct round reads polished and traditional; 1.5ct reads elevated; 2ct starts to feel bold. See how each looks on your hand in the Discovery Room.

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FAQ

Common questions

Why does a round cost more than an oval of the same carat?: Round brilliant wastes more of the diamond rough during cutting, and the demand is higher, so the per-carat price is typically 20–40% more.
How big does a 1ct round look?: A 1ct round is about 6.5mm across — a familiar, unmissable presence without being dramatic.
Round vs oval — which reads bigger?: An oval of the same carat weight reads roughly 15–20% bigger face-up because the shape stretches the outline.
Best setting for a round?: Solitaire is the classic; halo or hidden halo add sparkle and perceived size; pavé bands add finger-length sparkle without competing with the center.

More shape

Keep exploring.

Oval engagement rings, at true scale.

Ovals stretch a stone's face and finger-flatter without shouting. Here's how each carat weight actually reads on a hand.

Read →

Cushion cut, soft and romantic.

Cushions read pillowy and vintage. Here's how they compare face-up to round and oval at every carat weight.

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Emerald cut, quiet and architectural.

Emerald cuts read long and lean. See how each carat weight covers the finger and pairs with wedding bands.

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Pear cut, elegant and unmistakable.

Pears elongate the finger and photograph beautifully. Here's what to know about orientation, setting, and true scale.

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Radiant cut, brilliant and bold.

Radiants combine emerald-shape geometry with brilliant-cut sparkle. See how they compare at every carat weight.

Read →

Princess cut, sharp and modern.

Square, sparkly, and unmistakably 2000s-classic. Here's how princess reads at true scale today.

Read →