Princess Cut Diamond: Sizes, Price and Settings
By Jared James · Last updated 28 October 2026
Quick answer
A princess cut diamond is a square brilliant cut with sharp, uncut corners and plenty of sparkle. A 1 carat princess measures about 5.5 mm square and costs about $1,340 as a loose IGI-graded lab-grown stone on our builder, a little more than a round, and a complete 18k gold princess ring starts at $3,350. The sharp corners need protecting from chips, so look for V-prongs, a bezel or a halo.
Shape at a glance
| Detail | Typical detail | Buying note |
|---|---|---|
| Facet pattern | Square brilliant, often with 57 or more facets depending on the cut style. | It gives far more sparkle than a step-cut square shape like an Asscher. |
| Typical ratio | Around 1.00 to 1.05 for a square look. | A true square sits close to 1.00 and should not look stretched, unless you actually want a rectangular effect. |
| Sparkle | Bright and lively, with a crisp geometric outline. | Compare depth and face-up size, because some princess cuts carry their weight hidden underneath. |
| Best for | Modern solitaires, channel-set bands, halos and clean geometric designs. | Choose princess cut when you want crisp square geometry with strong sparkle. |
What is a Princess Cut Diamond?
A princess cut diamond is a square brilliant-cut diamond with sharp, uncut corners, and it manages to give a clean, geometric look while still throwing out plenty of sparkle.
It is less soft than a cushion and less open than an emerald cut, sitting somewhere crisper than both. Its one real practical issue is corner protection, because those sharp points are vulnerable if they are left exposed.
What size is a princess cut diamond at each carat weight?
A 1 carat princess measures about 5.5 mm square and a 2 carat about 6.9 by 6.8 mm. These are the typical sizes of the IGI-graded princess cuts on our builder, so they come from measured stones rather than a formula.
A princess is narrower than a round of the same weight, 5.5 mm against 6.5 mm at 1 carat, because more of its weight sits in the corners and the depth. Corner to corner it measures about 7.8 mm, so it still covers plenty of finger. Nearly all of our princess cuts sit between 1.00 and 1.05 length to width, so they read as a true square.
| Carat weight | Typical size (mm) |
|---|---|
| 1 carat | 5.5 x 5.5 |
| 1.5 carat | 6.3 x 6.3 |
| 2 carat | 6.9 x 6.8 |
| 2.5 carat | 7.5 x 7.3 |
| 3 carat | 7.9 x 7.8 |
| 4 carat | 8.7 x 8.6 |
Measured from the IGI-graded princess cut lab-grown diamonds on our builder feed on 28 October 2026, each weight band running to .09 of a carat (1 carat means 1.00 to 1.09 ct). Typical is the median stone.
How much does a princess cut lab-grown diamond cost?
About $1,340 at 1 carat and $2,600 at 2 carats on our builder, and a complete 18k gold princess ring starts at $3,350. Every stone we sell is graded by IGI at D to F colour and VS1 clarity or better, so these prices are for high grades, not entry-level stones.
Our complete princess rings come in three designs: the Skye solitaire, the Ana with a hidden halo and the Scarlett with a pavé band. The Ana comes at 1, 2 and 3 carats, and the Skye and Scarlett at every weight in the table.
| Carat weight | Typical loose stone | Most stones (middle 80%) | Complete 18k gold ring |
|---|---|---|---|
| 1 carat | $1,342 | $1,270 to $1,550 | $3,350 to $3,750 |
| 1.5 carat | $1,771 | $1,593 to $2,542 | $4,050 to $4,450 |
| 2 carat | $2,602 | $2,382 to $2,900 | $4,650 to $5,050 |
| 2.5 carat | $3,262 | $2,304 to $4,070 | $5,200 to $5,600 |
| 3 carat | $4,984 | $3,143 to $7,199 | $9,050 to $9,400 |
| 4 carat | $5,889 | $3,735 to $7,941 | $10,000 to $10,400 |
Loose stone prices from our builder feed and complete ring prices from our carat collections, 18k gold, checked 28 October 2026. Rings at other weights are made to order: choose the stone and setting in our ring builder.
Is a princess cut more expensive than a round?
Yes, with us, from 1 to 3 carats. A 1 carat princess on our builder is a median $1,342 against $1,242 for a round, and a 3 carat $4,984 against $3,809. Our complete 1 carat princess rings start at $3,350, against $3,200 for a round.
The usual advice that princess cuts are cheaper comes from mined diamonds, where the square shape keeps more of the rough crystal than a round does. Lab-grown prices don’t follow it. At 4 carats our typical princess was the cheaper of the two, though prices at that size spread widely for both shapes.
| Carat weight | Typical princess | Typical round |
|---|---|---|
| 1 carat | $1,342 | $1,242 |
| 1.5 carat | $1,771 | $1,646 |
| 2 carat | $2,602 | $2,503 |
| 2.5 carat | $3,262 | $2,828 |
| 3 carat | $4,984 | $3,809 |
| 4 carat | $5,889 | $7,362 |
Median loose stone prices for IGI-graded lab-grown diamonds, D to F colour and VS1 clarity or better, from our builder feed on 28 October 2026.
What to check before choosing
How to protect the corners of a princess cut diamond
The sharp corners are the most vulnerable part of a princess cut, so look for V-prongs, a bezel or a setting that physically covers each corner. This is the first practical thing to check for daily wear, especially on an engagement ring.
Face-up size of a princess cut diamond
Some princess cut diamonds carry a lot of weight deep in the pavilion, which means they can look smaller from above than their carat weight suggests. Compare the millimetre dimensions on the report rather than just the carat number, so you know how the stone will actually read on the hand.
Best colour grade for a princess cut diamond
Princess cut diamonds can show a little warmth near the corners, because colour tends to pool at the points. Every diamond we sell is D, E or F colour, so the corners stay white in platinum and white gold as well as in yellow or rose gold.
Round, 1.5 ct
A real 1.5 ct round side on: 7.4 mm across and 4.5 mm deep.
Princess, 1.47 ct
A real 1.47 ct princess at the same scale: narrower at 6.1 mm, and a little deeper at 4.6 mm.
Settings that suit this shape
- A 4-prong solitaire with V-prongs is the classic protective setting, and it keeps the look clean.
- A channel-set band pairs well with a princess cut, because square stones sit neatly in a row with no gaps.
- A halo adds size and tucks protection around the outline, though it does soften the clean square look a little.
Hidden halo
V-shaped claws cover each corner.
Pavé band
Small diamonds set along the band.
Who does princess cut suit?
Princess cut suits anyone who wants a crisp, modern square diamond with more sparkle than an emerald cut. It works best in structured designs where the corners are properly protected.
Watch for
- Exposed corners can chip if the ring is knocked, so the setting has to cover them.
- A deep stone can face up smaller than you expect for its carat weight.
- A slightly rectangular outline can be noticeable in a simple setting, so check the ratio if you want a true square.
Frequently asked questions
- What is a princess cut diamond?
- A princess cut diamond is a square brilliant-cut diamond with sharp, uncut corners. It is the most popular square shape for engagement rings, and it gives strong sparkle inside a clean, geometric outline.
- Are princess cut diamonds sparkly?
- Yes. Princess cuts use a brilliant-style facet pattern, so a well-cut princess shows strong fire and sparkle, not far off a round brilliant but in a square outline.
- What is the best clarity for a princess cut diamond?
- VS1 or better, which is what we sell. The brilliant facets help hide small inclusions, but check the exact stone for anything sitting near the corners, where a chip can start.
- Are princess cut diamonds cheaper than round?
- Not with us, from 1 to 3 carats. On our ring builder on 28 October 2026, a 1 carat princess cut lab-grown diamond was a median $1,342 against $1,242 for a round, and our complete 1 carat princess rings start at $3,350 against $3,200 for a round. Mined princess cuts can cost less than mined rounds, because the cut keeps more of the rough diamond.
- How big is a 1 carat princess cut diamond?
- About 5.5 mm square, against 6.5 mm across for a 1 carat round, measured on the princess cut lab-grown diamonds on our builder. Corner to corner it is about 7.8 mm.
- What is the difference between a princess cut and a round diamond?
- A round brilliant has a circular outline and the most standardised sparkle, and it is the only common shape with a formal cut grade. A princess cut is square with sharp corners and gives a more modern geometric look, though those corners need extra protection. On our ring builder a lab-grown princess costs a little more than a round of the same weight from 1 to 3 carats.
- Are princess cut diamonds good for engagement rings?
- Yes. Princess cuts are hard-wearing for daily wear as long as the corners are protected by V-prongs, a bezel, a halo or a channel setting. They look especially good in clean, modern designs.
