A 1.5 carat round and a 1.5 carat oval weigh exactly the same. One of them will look noticeably bigger on your hand.
Carat is a measure of weight, not size. How that weight is distributed is what your eye actually responds to.
Shapes That Read Larger
Oval. The elongated outline covers more of the finger. A reliable choice for maximum presence.
Pear. Similar spread to an oval with a tapered point that draws the eye down the finger.
Marquise. The most elongated of the classic shapes and the most dramatic in terms of apparent size.
Cushion. Softer and more vintage in feel, and generally reads a little larger than a round.
Shapes That Read True to Weight
Round brilliant. The reference point. Unmatched for brilliance, but more of its weight sits in the depth of the stone.
Emerald and asscher. Step cuts with a clean, architectural look. They trade some sparkle for clarity of line, and inclusions are easier to see, so clarity matters more here.
The Practical Takeaway
If size on the hand is your priority, look at ovals, pears and cushions before rounds. If brilliance is the priority, a well cut round is very hard to beat.
We carry all of these shapes in IGI and DIA certified lab grown, and you are welcome to compare them side by side in Rivonia.