Diamond conversion.
Pick a shape, choose a size and see the carat weight instantly — or go the other way, from carat to millimetres. Every result comes with a to-scale preview.
1 · Shape Round
2 · Convert
Values are approximate and based on standard cut proportions. Actual weight can vary slightly with depth and girdle thickness.
Understanding diamond sizes.
Choosing a diamond can feel overwhelming. Our charts help you visualise and compare sizes, so you can find the right stone with confidence.
Why diamond size matters
Size shapes both the look and the value of a diamond. Carat is a measure of weight, but the millimetre dimensions decide how big it actually looks — a well-proportioned diamond can face up larger and more brilliant.
How to use the chart
- Visual comparison: see the actual size of each stone at a glance.
- Carat ⇄ millimetre: understand how carat weight translates into real dimensions.
- Ideal proportions: find typical dimensions for each shape and cut.
Tips for choosing the right size
- Personal preference: consider how visible the wearer wants the diamond to be.
- Setting style: halos and thin bands make a centre stone look larger.
- Finger size: the same diamond looks more prominent on a slimmer finger.
- Elongated shapes: ovals, pears and marquise look bigger than a round of the same carat.
Get expert assistance
Our experts are here to guide you through every step — whether it's an engagement ring, a special gift or a timeless addition to your collection.
Tell us the size — we'll find the stone.
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