Size guides › Princess
Princess diamonds
Princess diamond size chart
A crisp square with sharp corners and plenty of sparkle. A princess is a square brilliant cut with pointed corners. It's the most popular square shape, very lively, and usually less expensive per carat than a round.
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Every princess size, drawn to scale
From 0.25 to 3 carats, on a millimeter grid. Tap a size to jump to it.
| Carat | Size (mm) | Looks like a round of | Covers of a size 6 finger |
|---|---|---|---|
| 0.25 ct | 3.46 × 3.46 mm | 0.22 ct | 20% |
| 0.5 ct | 4.35 × 4.35 mm | 0.45 ct | 25% |
| 0.75 ct | 4.98 × 4.98 mm | 0.67 ct | 28% |
| 1 ct | 5.49 × 5.49 mm | 0.89 ct | 31% |
| 1.25 ct | 5.91 × 5.91 mm | 1.11 ct | 33% |
| 1.5 ct | 6.28 × 6.28 mm | 1.34 ct | 36% |
| 2 ct | 6.91 × 6.91 mm | 1.78 ct | 39% |
| 2.5 ct | 7.44 × 7.44 mm | 2.23 ct | 42% |
| 3 ct | 7.91 × 7.91 mm | 2.67 ct | 45% |
Typical proportions. Real stones vary by a few tenths of a millimeter — the certificate gives the exact size.
What to know about princess diamonds
Protect the corners
The sharp corners are where a princess is most likely to chip. Prongs that cover each corner protect them.
Better value per carat
A princess uses more of the rough crystal than a round does, which is a big part of why it usually costs less per carat.
Deep for its size
It's cut deep, so a princess looks smaller from above than its weight suggests — compare by millimeters.
Princess vs round
The dashed line is a 1 ct round. A 1 ct princess covers about 7% less area from above.
Size by size
Every princess weight, answered
0.25 carat princess
How big is a 0.25 carat princess diamond?
About 3.5 × 3.5 mm, and it looks about as big as a 0.22 ct round. It's about a fifth the width of a US dime (17.91 mm).
Small and delicate
A quarter carat reads as a bright point of sparkle rather than a statement. It's a lovely size for minimalist and stacking rings and for anyone who wants something that sits close and never catches, and it leaves room in the budget for a better cut or color. As a princess, it looks about 7% smaller from above than a round of the same weight, because more of the weight sits underneath — so it reads like the size below.
Want it to look bigger?
A halo of small diamonds around it takes the face-up width from 3.46 mm to about 4.8 mm — 38% wider — for much less than a bigger center stone would cost.
Cover the corners
A 0.25 ct princess has four sharp corners 3.5 mm apart, and they're where it chips. Choose prongs that sit over each corner.
The same size in other shapes
To cover the same area from above you'd need about 0.22 ct in a round, 0.20 ct in an oval and 0.26 ct in a cushion.
Settings
- Made to orderSolitaire, halo, three stone, bezel, cathedral and east–west — the ready-made heads we could find are for round and oval stones, so ask for one made at 3.5 mm.
Shop a 0.25 ct princess: Blue Nile · Blue Nile, lab-grown · With Clarity · Rare Carat
Blue Nile opens already narrowed to 0.23–0.27 ct at a length-to-width ratio of 0.95 to 1.05 — the range of weights a stone this size can be — so the first page of results is this size rather than every princess they carry. It also asks for a well-cut princess's depth (67–78%) and table (65–75%).
0.5 carat princess
How big is a 0.5 carat princess diamond?
About 4.4 × 4.4 mm, and it looks about as big as a 0.45 ct round. It's about a quarter the width of a US dime (17.91 mm).
Petite and practical
Half a carat is a classic petite size: noticeable without being showy, comfortable for everyday wear, and easy to set low so it doesn't snag on gloves or knitwear. As a princess, it looks about 7% smaller from above than a round of the same weight, because more of the weight sits underneath — so it reads like the size below.
Consider 0.45 ct
Prices tend to step up at round weights like 0.5 ct. A 0.45 ct princess measures about 4.20 × 4.20 mm — only 0.15 mm narrower, with 7% less area on top. That's very hard to see on a hand.
Want it to look bigger?
A halo of small diamonds around it takes the face-up width from 4.35 mm to about 6.0 mm — 38% wider — for much less than a bigger center stone would cost.
Cover the corners
A 0.5 ct princess has four sharp corners 4.4 mm apart, and they're where it chips. Choose prongs that sit over each corner.
The same size in other shapes
To cover the same area from above you'd need about 0.45 ct in a round, 0.40 ct in an oval and 0.53 ct in a cushion.
Settings
- Made to orderSolitaire, halo, three stone, bezel, cathedral and east–west — the ready-made heads we could find are for round and oval stones, so ask for one made at 4.4 mm.
Shop a 0.5 ct princess: Blue Nile · Blue Nile, lab-grown · With Clarity · Rare Carat
Blue Nile opens already narrowed to 0.47–0.54 ct at a length-to-width ratio of 0.95 to 1.05 — the range of weights a stone this size can be — so the first page of results is this size rather than every princess they carry. It also asks for a well-cut princess's depth (67–78%) and table (65–75%).
0.75 carat princess
How big is a 0.75 carat princess diamond?
About 5.0 × 5.0 mm, and it looks about as big as a 0.67 ct round. It's about a quarter the width of a US dime (17.91 mm).
Just under the milestone
Three-quarters of a carat gives a good share of the look of a one-carat stone, and on a slim finger the difference can be hard to see. It's a sensible size if the budget is better spent on cut quality or the setting. As a princess, it looks about 7% smaller from above than a round of the same weight, because more of the weight sits underneath — so it reads like the size below.
Want it to look bigger?
A halo of small diamonds around it takes the face-up width from 4.98 mm to about 6.9 mm — 38% wider — for much less than a bigger center stone would cost.
Cover the corners
A 0.75 ct princess has four sharp corners 5.0 mm apart, and they're where it chips. Choose prongs that sit over each corner.
The same size in other shapes
To cover the same area from above you'd need about 0.67 ct in a round, 0.59 ct in an oval and 0.79 ct in a cushion.
Settings
- Made to orderSolitaire, halo, three stone, bezel, cathedral and east–west — the ready-made heads we could find are for round and oval stones, so ask for one made at 5 mm.
Shop a 0.75 ct princess: Blue Nile · Blue Nile, lab-grown · With Clarity · Rare Carat
Blue Nile opens already narrowed to 0.70–0.80 ct at a length-to-width ratio of 0.95 to 1.05 — the range of weights a stone this size can be — so the first page of results is this size rather than every princess they carry. It also asks for a well-cut princess's depth (67–78%) and table (65–75%).
1 carat princess
How big is a 1 carat princess diamond?
About 5.5 × 5.5 mm, and it looks about as big as a 0.89 ct round. It's about a third the width of a US dime (17.91 mm).
The milestone size
One carat is the size many people picture when they think of an engagement ring. It's clearly a center stone without being heavy, and it suits almost every setting style. As a princess, it looks about 7% smaller from above than a round of the same weight, because more of the weight sits underneath — so it reads like the size below.
Consider 0.9 ct
Prices tend to step up at round weights like 1 ct. A 0.9 ct princess measures about 5.30 × 5.30 mm — only 0.19 mm narrower, with 7% less area on top. That's very hard to see on a hand.
Cover the corners
A 1 ct princess has four sharp corners 5.5 mm apart, and they're where it chips. Choose prongs that sit over each corner.
The same size in other shapes
To cover the same area from above you'd need about 0.89 ct in a round, 0.79 ct in an oval and 1.06 ct in a cushion.
Settings
- Made to orderSolitaire, halo, three stone, bezel, cathedral and east–west — the ready-made heads we could find are for round and oval stones, so ask for one made at 5.5 mm.
Shop a 1 ct princess: Blue Nile · Blue Nile, lab-grown · With Clarity · Rare Carat
Blue Nile opens already narrowed to 0.93–1.07 ct at a length-to-width ratio of 0.95 to 1.05 — the range of weights a stone this size can be — so the first page of results is this size rather than every princess they carry. It also asks for a well-cut princess's depth (67–78%) and table (65–75%).
1.25 carat princess
How big is a 1.25 carat princess diamond?
About 5.9 × 5.9 mm, and it looks about as big as a 1.11 ct round. It's about a third the width of a US dime (17.91 mm).
A step past one carat
A quarter carat over the milestone. It reads as noticeably substantial on most hands while still sitting comfortably in standard settings, and it avoids the round-number weights where prices tend to jump. As a princess, it looks about 7% smaller from above than a round of the same weight, because more of the weight sits underneath — so it reads like the size below.
Cover the corners
A 1.25 ct princess has four sharp corners 5.9 mm apart, and they're where it chips. Choose prongs that sit over each corner.
The same size in other shapes
To cover the same area from above you'd need about 1.11 ct in a round, 0.99 ct in an oval and 1.32 ct in a cushion.
Settings
- Made to orderSolitaire, halo, three stone, bezel, cathedral and east–west — the ready-made heads we could find are for round and oval stones, so ask for one made at 5.9 mm.
Shop a 1.25 ct princess: Blue Nile · Blue Nile, lab-grown · With Clarity · Rare Carat
Blue Nile opens already narrowed to 1.16–1.34 ct at a length-to-width ratio of 0.95 to 1.05 — the range of weights a stone this size can be — so the first page of results is this size rather than every princess they carry. It also asks for a well-cut princess's depth (67–78%) and table (65–75%).
1.5 carat princess
How big is a 1.5 carat princess diamond?
About 6.3 × 6.3 mm, and it looks about as big as a 1.34 ct round. It's about a third the width of a US dime (17.91 mm).
A clear statement
At a carat and a half, the stone is the first thing people notice about the ring. It's still easy to wear every day, but cut quality starts to show more, because there's more stone to see. As a princess, it looks about 7% smaller from above than a round of the same weight, because more of the weight sits underneath — so it reads like the size below.
Consider 1.4 ct
Prices tend to step up at round weights like 1.5 ct. A 1.4 ct princess measures about 6.14 × 6.14 mm — only 0.14 mm narrower, with 4% less area on top. That's very hard to see on a hand.
Cover the corners
A 1.5 ct princess has four sharp corners 6.3 mm apart, and they're where it chips. Choose prongs that sit over each corner.
The same size in other shapes
To cover the same area from above you'd need about 1.34 ct in a round, 1.19 ct in an oval and 1.58 ct in a cushion.
Settings
- Made to orderSolitaire, halo, three stone, bezel, cathedral and east–west — the ready-made heads we could find are for round and oval stones, so ask for one made at 6.3 mm.
Shop a 1.5 ct princess: Blue Nile · Blue Nile, lab-grown · With Clarity · Rare Carat
Blue Nile opens already narrowed to 1.40–1.60 ct at a length-to-width ratio of 0.95 to 1.05 — the range of weights a stone this size can be — so the first page of results is this size rather than every princess they carry. It also asks for a well-cut princess's depth (67–78%) and table (65–75%).
2 carat princess
How big is a 2 carat princess diamond?
About 6.9 × 6.9 mm, and it looks about as big as a 1.78 ct round. It's about two-fifths the width of a US dime (17.91 mm).
A large stone
Two carats is big on most hands and is seen from across a room. At this size clarity and color are easier to judge by eye, and a secure head matters more, so ask how it's set. As a princess, it looks about 7% smaller from above than a round of the same weight, because more of the weight sits underneath — so it reads like the size below.
Consider 1.9 ct
Prices tend to step up at round weights like 2 ct. A 1.9 ct princess measures about 6.79 × 6.79 mm — only 0.12 mm narrower, with 3% less area on top. That's very hard to see on a hand.
Cover the corners
A 2 ct princess has four sharp corners 6.9 mm apart, and they're where it chips. Choose prongs that sit over each corner.
The same size in other shapes
To cover the same area from above you'd need about 1.78 ct in a round, 1.59 ct in an oval and 2.11 ct in a cushion.
Settings
- Made to orderSolitaire, halo, three stone, bezel, cathedral and east–west — the ready-made heads we could find are for round and oval stones, so ask for one made at 6.9 mm.
Shop a 2 ct princess: Blue Nile · Blue Nile, lab-grown · With Clarity · Rare Carat
Blue Nile opens already narrowed to 1.86–2.14 ct at a length-to-width ratio of 0.95 to 1.05 — the range of weights a stone this size can be — so the first page of results is this size rather than every princess they carry. It also asks for a well-cut princess's depth (67–78%) and table (65–75%).
2.5 carat princess
How big is a 2.5 carat princess diamond?
About 7.4 × 7.4 mm, and it looks about as big as a 2.23 ct round. It's about two-fifths the width of a US dime (17.91 mm).
Very large
Two and a half carats is a very large stone for everyday wear. Setting height starts to matter: a lower head snags less, and a sturdy one protects a stone this valuable. Many owners have it appraised for insurance. As a princess, it looks about 7% smaller from above than a round of the same weight, because more of the weight sits underneath — so it reads like the size below.
Cover the corners
A 2.5 ct princess has four sharp corners 7.4 mm apart, and they're where it chips. Choose prongs that sit over each corner.
The same size in other shapes
To cover the same area from above you'd need about 2.23 ct in a round, 1.98 ct in an oval and 2.64 ct in a cushion.
Settings
- Made to orderSolitaire, halo, three stone, bezel, cathedral and east–west — the ready-made heads we could find are for round and oval stones, so ask for one made at 7.4 mm.
Shop a 2.5 ct princess: Blue Nile · Blue Nile, lab-grown · With Clarity · Rare Carat
Blue Nile opens already narrowed to 2.33–2.68 ct at a length-to-width ratio of 0.95 to 1.05 — the range of weights a stone this size can be — so the first page of results is this size rather than every princess they carry. It also asks for a well-cut princess's depth (67–78%) and table (65–75%).
3 carat princess
How big is a 3 carat princess diamond?
About 7.9 × 7.9 mm, and it looks about as big as a 2.67 ct round. It's about two-fifths the width of a US dime (17.91 mm).
Dramatic
Three carats is a show-stopping size. It dominates all but the broadest fingers, so seeing it on your own hand before buying matters more here than at any other size. Look for a head made for a stone this size, and insure it. As a princess, it looks about 7% smaller from above than a round of the same weight, because more of the weight sits underneath — so it reads like the size below.
Consider 2.9 ct
Prices tend to step up at round weights like 3 ct. A 2.9 ct princess measures about 7.82 × 7.82 mm — only 0.09 mm narrower, with 2% less area on top. That's very hard to see on a hand.
Cover the corners
A 3 ct princess has four sharp corners 7.9 mm apart, and they're where it chips. Choose prongs that sit over each corner.
The same size in other shapes
To cover the same area from above you'd need about 2.67 ct in a round, 2.38 ct in an oval and 3.17 ct in a cushion.
Settings
- Made to orderSolitaire, halo, three stone, bezel, cathedral and east–west — the ready-made heads we could find are for round and oval stones, so ask for one made at 7.9 mm.
Shop a 3 ct princess: Blue Nile · Blue Nile, lab-grown · With Clarity · Rare Carat
Blue Nile opens already narrowed to 2.79–3.21 ct at a length-to-width ratio of 0.95 to 1.05 — the range of weights a stone this size can be — so the first page of results is this size rather than every princess they carry. It also asks for a well-cut princess's depth (67–78%) and table (65–75%).
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See a princess on your own hand
Pick a size, add a photo of your hand, and see it at its real size — with the fit check built in.
Questions
How big is a 0.25 carat princess diamond?
About 3.46 × 3.46 mm, and it looks about as big as a 0.22 carat round.
How big is a 0.5 carat princess diamond?
About 4.35 × 4.35 mm, and it looks about as big as a 0.45 carat round.
How big is a 0.75 carat princess diamond?
About 4.98 × 4.98 mm, and it looks about as big as a 0.67 carat round.
How big is a 1 carat princess diamond?
About 5.49 × 5.49 mm, and it looks about as big as a 0.89 carat round.
How big is a 1.25 carat princess diamond?
About 5.91 × 5.91 mm, and it looks about as big as a 1.11 carat round.
How big is a 1.5 carat princess diamond?
About 6.28 × 6.28 mm, and it looks about as big as a 1.34 carat round.
How big is a 2 carat princess diamond?
About 6.91 × 6.91 mm, and it looks about as big as a 1.78 carat round.
How big is a 2.5 carat princess diamond?
About 7.44 × 7.44 mm, and it looks about as big as a 2.23 carat round.
How big is a 3 carat princess diamond?
About 7.91 × 7.91 mm, and it looks about as big as a 2.67 carat round.
Do princess diamonds look bigger than round ones?
No. At the same weight a princess covers about 7% less area from above than a round, because it's cut deeper.
What size setting does a princess diamond need?
Any common style can be made to fit it: ask for a head the size of the stone — about 5.5 mm for a 1 ct. Ready-made heads are mostly listed for round stones, so for a princess choose a setting made to order.