How big a carat actually looks
A carat is a weight, not a width, so the number on a product page does not tell you how much finger a stone covers. This page draws round brilliants at their real size. Set the scale against a bank card, then pick a weight and a ring size.
See it on a finger
Pick a weight and the ring size you wear. The band is drawn at the width of a finger that takes that size, so the stone sits against something close to the right scale. If you do not know the size, there is a ring sizer you can print.
Every weight side by side
The same stones, drawn together. Doubling the weight from one carat to two adds about 1.7 mm across the top, so the stone is twice as heavy and reads perhaps a quarter wider.
Carat weights, drawn to scale once you have set it.
The numbers
These are round brilliants. An elongated cut spreads its weight over a longer outline and covers more finger for the same weight, so an oval, a marquise or a pear reads larger than the figures here. Our guide to carat weight covers how shape and setting change what you see.
| Carat weight | Diameter across the top |
|---|---|
| 0.25 ct | 4.1 mm |
| 0.33 ct | 4.5 mm |
| 0.50 ct | 5.2 mm |
| 0.75 ct | 5.9 mm |
| 1.00 ct | 6.5 mm |
| 1.25 ct | 7.0 mm |
| 1.50 ct | 7.4 mm |
| 2.00 ct | 8.2 mm |
| 2.50 ct | 8.8 mm |
| 3.00 ct | 9.4 mm |
| 4.00 ct | 10.3 mm |
| 5.00 ct | 11.1 mm |
What this page cannot tell you
The same stone reads as substantial on a slender finger and restrained on a broader one, and a halo or a wide band changes it again. No chart settles that. Write to us and describe the hand it is going on, and we will talk it through.