Carat Weight vs Face-Up Size

Quick answer: Carat weight measures how heavy a diamond is (1 carat = 0.2 grams). Face-up size is how big it looks from above, measured in millimeters. Two diamonds of the same carat can look very different in size depending on shape and cut. Elongated shapes like marquise, oval and pear look largest per carat, while deep cuts and step cuts like Asscher can look smaller. When comparing stones, check millimeters, not just carats.

Carat Weight vs Face-Up Size

Which Shapes Look Largest?

1. Marquise (largest face-up per carat)
2. Oval and pear
3. Emerald and radiant (rectangular)
4. Round
5. Cushion, princess and Asscher (more weight in depth)

Shown: 0.40 Ct Marquise Shape D Color VS1 Lab Grown Diamond

Tips to Get the Most Size

• Choose an elongated shape.
• Check that depth % is in the ideal range; avoid overly deep stones.
• Buy just under round numbers (e.g., 0.95 ct instead of 1.00 ct) to save.
• Add a halo or thin band to make the center look larger.
• Consider lab grown or moissanite for more size per dollar.

See our diamond size chart and table and depth guide.

Loose Lab Diamonds at Ivevar

We list measurements for our loose lab diamonds and can set any stone in the ring you choose, in our Surat workshop. Every order ships free worldwide and comes with 30-day easy returns. Browse marquise lab diamonds.

Shop Marquise Lab Diamonds

0.40 Ct D VS1 MarquiseShop Now0.34 Ct D VS1 MarquiseShop Now0.36 Ct D VS1 MarquiseShop Now0.37 Ct D VS1 MarquiseShop Now0.39 Ct D VS1 MarquiseShop Now0.41 Ct D VS1 MarquiseShop Now

Swipe to see more → | View marquise lab diamonds

Frequently Asked Questions

Is carat the same as size?

No. Carat is weight; size is measured in millimeters.

Which shape looks biggest?

Marquise, followed by oval and pear.

Why does a deep diamond look smaller?

More weight sits below the girdle, out of view.

Should I compare mm or carat?

Compare mm for size, carat for price.

Does a halo add size?

Yes, visually.

The Bottom Line

Carat drives price; millimeters show size. Compare both, and choose a shape and cut that maximize the look you want.

Related Guides

• Carat size on the hand
• Moissanite size chart
• Marquise vs oval

Author Bio

Aumsri Pradhan

Founder, Ivevar Luxury

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Aumsri Pradhan is the founder of Ivevar Luxury, a Surat-based fine jewelry brand that designs and handcrafts lab grown diamond and moissanite jewelry in its own workshop. She leads the brand's design and customer experience, from engagement rings and bridal sets to custom pieces made to each client's story. Through the Ivevar blog, she shares practical guidance on lab grown diamonds, moissanite, diamond grading and ring design to help buyers choose with confidence.

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