A 1.5-carat lab-grown diamond is a noticeable step up from a 1-carat: about 15% wider in a round, with clearly more presence on the hand. In lab-grown, that extra size is affordable. Certified 1.5-carat stones in our catalogue start well below €1,000.
This guide covers how big a 1.5-carat diamond is by shape, how it compares with 1 and 2 carats, what real 1.5-carat stones cost, and which grades give the best value. For the 1-carat comparison, see how big a 1-carat diamond is.
How big is a 1.5-carat diamond?
A well-cut 1.5-carat round measures approximately 7.3 to 7.5 mm across, compared with about 6.4 mm for a 1-carat. Approximate face-up sizes by shape:
| Shape | Approximate size of a 1.50 ct stone |
|---|---|
| Round | about 7.4 mm diameter |
| Oval | about 9 × 6.5 mm |
| Princess | about 6.4 × 6.4 mm |
| Cushion | about 6.8 × 6.8 mm |
| Emerald | about 7.8 × 5.6 mm |
| Marquise | about 14 × 7 mm |
The report gives the exact measurements of each stone, and those are the ones to trust.
1 carat vs 1.5 carat vs 2 carat
| Weight | Approximate round diameter | Look on the hand |
|---|---|---|
| 1.00 ct | about 6.4 mm | Classic, refined |
| 1.50 ct | about 7.4 mm | Clearly larger, still easy to wear |
| 2.00 ct | about 8.1 mm | Bold, statement |
For many people, 1.5 carats is the sweet spot: it looks generous without feeling oversized. If you are thinking bigger, our 2-carat price guide shows what that costs.
How much is a 1.5-carat lab-grown diamond?
These are real listings from our catalogue on 26 October 2026. Each listing shows its current price.
| Stone | Price on 26 October 2026 |
|---|---|
| 1.56 ct oval, E colour, SI1 | €510 |
| 1.5 ct princess, H colour, VS1 | €550 |
| 1.5 ct marquise, F colour, VS2 | €610 |
| 1.5 ct emerald, F colour, VVS2 | €590 |
| 1.50 ct round, F colour, VS1 | €850 |
On that date, the lowest-priced stone in our 1.5-carat collection was €380. Browse all 1.5-carat lab-grown diamonds, or go straight to 1.5-carat round diamonds.
Best grades for a 1.5-carat diamond
Cut
Cut has the biggest effect on sparkle. For a round, choose Excellent or Ideal. For fancy shapes, check symmetry and look at the photos or video.
Colour
At 1.5 carats, G or H colour looks white once set for most people. Choose E–F if you want the brightest look in white gold or platinum. See our near-colorless guide.
Clarity
VS2 or SI1 is usually clean to the eye in brilliant shapes like round and oval. For emerald and other step cuts, VS1 or better is safer.
Is a 1.5-carat diamond good for an engagement ring?
Yes. It is large enough to stand out, and still sits comfortably on most hands. In lab-grown, a 1.5-carat stone and a setting from about €490 can come in under the price of a much smaller mined diamond. Design yours in our ring customizer, or read our engagement ring guide.
We search over 350,000 IGI- and GIA-certified lab-grown stones from about €380, with free EU shipping, no import duties and a 30-day return.
Frequently asked questions
How many mm is a 1.5-carat diamond?
A well-cut 1.5-carat round is approximately 7.3 to 7.5 mm across. Fancy shapes vary; an oval is roughly 9 × 6.5 mm.
Is 1.5 carats much bigger than 1 carat?
Yes, it is visible. A 1.5-carat round is about 1 mm wider than a 1-carat, and its face-up area is roughly a third larger.
What is the cheapest 1.5-carat lab-grown diamond?
On 26 October 2026, the lowest-priced stone in our 1.5-carat collection was €380. Prices change as stones sell.
Which shape looks biggest at 1.5 carats?
Marquise, pear and oval look largest face-up for their weight. See our marquise guide.
Are 1.5-carat lab-grown diamonds certified?
Yes. Every stone we sell has an IGI or GIA grading report.
How we wrote this guide: written by the VAALBERG team. Prices are individual listings from our own catalogue on the date shown; sizes are approximate and the report measurements are authoritative.
