3 Carat Diamond Engagement Rings
Discover your perfect 3 carat diamond ring, with our curated selection of sublime ring designs, complete with your choice of exquisite 3 carat diamond.
Each 3ct ring ring can be set with a natural or lab grown diamond and is made to order in our Hatton Garden workshop, where you can see our goldsmiths at work.
Most rings shown with 1ct diamond
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We get it, you’ve never done this before.
That’s why we have diamond and design experts on hand, who are here to guide you through every step - from understanding what carat, colour, cut and clarity mean, to designing the perfect ring.
About 3 Carat Diamond Rings
If you choose a 3 carat engagement ring, you’ll be choosing a ring that beautifully balances extravagance and contemporary taste. Considerably larger than the average engagement ring diamond size, a 3 carat diamond ring is big and sumptuous without looking over the top – suited best to super refined and stripped-back designs like solitaire rings and diamond band rings.
How much does a 3 carat diamond ring cost?
See how much a 3ct diamond ring costs below or compare the price of a 3 carat diamond to other carat sizes.
| Diamond Carat | Lab Diamond (D, VS1) | Natural Diamond (D, VS1) |
|---|---|---|
| 2ct | £2,430 | £26,700 |
| 3ct | £3,550 | £46,210 |
| 4ct | £5,040 | £87,280 |
At 3ct, the choice between a lab grown and a natural diamond sets your budget more than anything else. Natural diamonds of this size are exceptionally rare, so the price gap between the two is wider at 3ct than at any smaller weight.
Once you've made that choice, cut, colour, clarity and shape decide the rest, followed by the setting and metal. For more detail, take a look at what affects diamond price
If you'd like to get more from your 3ct budget, follow the tips below:
- Prioritise cut: On a diamond this size, cut quality is what makes it look lively rather than glassy.
- Choose an elongated shape: An oval, pear or marquise looks larger face up than a round of the same weight, so it delivers more presence for the price.
Because large diamonds vary so much, the best way to see real prices is to browse our loose lab grown diamonds and loose natural diamonds filtered to 3ct. Don't forget to add the cost of setting to your total, which starts at £1,195.
| What affects the price of a 3ct diamond ring? | How it affects price |
|---|---|
| Lab grown or natural | The biggest single factor. Natural diamonds of 3ct are rare, and price per carat climbs steeply as size increases, so a natural 3ct costs far more than three 1ct diamonds. Lab grown diamonds make this size accessible to many more budgets. |
| Cut | At 3ct, cut affects size as well as sparkle. A diamond cut too deep carries weight underneath where you can’t see it, so it can look smaller face up than a well-proportioned diamond of the same weight. An Excellent or Ideal cut makes the most of every carat. |
| Colour | Larger diamonds show their natural body colour more readily, so a faint tint that’s hard to spot at 1ct can be visible at 3ct. Higher colour grades cost more. Our natural diamonds are all D–F colour, graded colourless. |
| Clarity | Bigger facets make inclusions easier to see, especially in step cuts such as emerald and Asscher, which have open, mirror-like facets. Higher clarity grades cost more, and every diamond comes with an independent certificate showing its clarity grade. |
| Shape | Rounds usually cost the most per carat, because more of the rough diamond is lost in cutting and demand is high. Fancy shapes often cost less per carat, and elongated shapes such as oval, pear and marquise look larger face up than a round of the same weight. |
| Setting and metal | At 3ct, the centre diamond makes up most of the ring's cost, so the setting is a smaller share than at lighter weights. A larger diamond needs a secure setting, and our designers will advise on claws and profile. Platinum and 18K gold are priced differently. |
"At 3ct, the diamond does all the talking, so the details matter more than ever. Get the cut right, choose a colour that stays crisp and white, and you'll have a ring that looks every bit as impressive as it should."
Lab grown or natural: Choosing your 3 carat diamond
A lab grown diamond is still a diamond, with the same physical, chemical and optical properties as one formed in the earth. For many couples, it's what makes a 3ct centre stone possible, often with room in the budget for a higher grade.
A natural 3ct diamond is a rare find, and if rarity matters to you, it's hard to beat. Our natural diamonds are all D–F colour, graded colourless – which counts for more on a larger diamond, where any tint is easier to see. Every diamond we sell, natural or lab grown, is independently certified by a grading institution such as the GIA or IGI.
Explore our lab grown diamond engagement rings, compare loose natural diamonds, or read our guide to lab grown vs natural diamonds for more insight.
Shop 3 carat rings by shape
The bigger the diamond, the more shape it shows. At 3ct, the cut you choose sets the whole character of the ring. Take a look at the most popular 3ct diamond shapes below.
3 carat oval diamond rings
The most searched-for shape at 3ct. An oval's length makes it look larger than a round of the same weight – about 11mm long against about 9.5mm across for a 3ct round – and it sits elegantly on the finger. A slim solitaire band lets it take centre stage.
3 carat emerald cut diamond rings
Clean lines and long step facets give an emerald cut a classic, architectural look. Its open facets act like a window into the diamond, so at 3ct our gemmologists typically recommend higher clarity and colour grades.
3 carat marquise diamond rings
A marquise has one of the largest face-up areas of any shape for its weight, so a 3ct marquise is a true statement. Claws at each point help protect the tips.
3 carat radiant cut diamond rings
A radiant has the rectangular outline of an emerald cut with brilliant facets, giving more sparkle and doing more to hide inclusions.
For a more classic look, take a look at our round engagement rings or filter the 3ct collection on this page by shape.
How big is a 3 carat diamond?
It's important to remember that carat measures weight rather than size. A 3 carat diamond weights 0.6 grams. A 3ct round measures about 9.5mm across and a 3ct oval about 11mm long. On the hand, it's definitely a diamond people will notice from across the room.
| Diamond shape | Approximate size at 3ct |
|---|---|
| Round | About 9.5mm across |
| Oval | About 11mm long |
| Emerald | About 9.7mm long |
| Marquise | About 15mm long |
| Radiant | About 9mm long |
| Pear | About 9mm long |
| Princess | About 8.6mm across |
Compare other carat weights
These figures are standard approximation because sizes vary with each diamond's proportions.T o see 3ct next to smaller weights, take a look at our engagement ring carat size guide.
Not set on exactly 3ct? Take a look at our 2 carat, 2.5 carat, 3.5 carat and 4 carat diamond rings, or read our guide to diamond carat to see how weight affects size and price.
Popular 3ct diamond ring styles
You want your ring design to be timeless, and we get that. Our collection features rings that transcend trends, look great from every angle and are made to last a lifetime.
Try filtering your search by our core engagement ring styles to find the right style for you:
Ethically sourced & certified
The modern way to buy loose diamonds for your engagement ring, with real 360° videos and advanced filtering to help you make the most informed decision. Filter by carat weight, colour, clarity, cut, and more.
Whether you're looking for a lab grown diamond or natural centre stone, find the perfect loose diamond from our responsibly sourced collection of certified diamonds.
Exquisite craftsmanship
Each Queensmith engagement ring is crafted to order, made just for you and your partner. We have an in-house workshop and production team that meticulously crafts your ring and finesses every detail until it passes our final quality control check. Our quality and finish is a cut above the rest.
As part of our commitment to you, we offer a Lifetime Care Package including manufacturer's warranty, free servicing, free resizing and free cleaning, fully inclusive with every ring made by us.
Become an expert
Read our rich and detailed guides on everything there is to know about rings and diamonds, to help you create the best engagement ring for you.
Learn About 3ct Diamond Rings
Do you have additional questions? No problem, let us help you through the process
The cost of a 3 carat diamond ring depends on whether you choose a lab grown or natural diamond, then on cut, colour, clarity, shape and setting.
See "How much does a 3 carat diamond ring cost?" above for a look at our live 3ct diamond price table in more detail.
A round 3 ct diamond has a diameter around 9.5mm. This can vary a tiny bit, depending on the cut ratios of the diamond - but you can use that as a ballpark size to help visualise how big a 3ct diamond will look on your finger. Elongated shapes, like oval diamonds, appear larger due to an increased spread of carat over the surface area.
A 3ct oval diamond measures around 11.05mm in length. This is 2mm lengthier than a 2ct round diamond. The length and proportions of a 3ct oval diamond will vary a little depending on how it has been cut - some ovals are longer and skinnier, and others shorter and more rounded.
A 3 carat diamond engagement ring is large enough to stand out and is considerably larger than the average engagement ring diamond size.
Most people would agree a 3 carat diamond isn’t too big, particularly if it is set in a demure and refined ring style like a solitaire – but for others, a 3 carat ring might not be practical.
Some people’s jobs may prevent them from wearing a large diamond, while it could suit other people’s lifestyles perfectly.
For everyday wear, a lower setting like a solitaire or a diamond band design keeps the diamond closer to the finger and less likely to knock or catch. Our design consultants can show you how different settings feel on the hand.
More popular than you might think. In our latest Lab Grown Diamond Trends Report, 15% of Queensmith clients who chose a lab grown diamond went for 3ct or larger, including 4% who chose 4ct or above.
Lab grown diamonds have put a 3ct centre stone within reach of many more couples, so a size that was once rare is now a choice we see regularly.
On this page, 3 carat refers to the centre diamond. Some rings are described by total carat weight (TCW) instead, which adds up every diamond in the ring – so a trilogy ring listed at 3ct TCW has a much smaller centre stone than a 3ct solitaire.
What you'll pay for a 3 carat diamond depends on whether it's lab grown or natural and on its cut, colour, clarity and shape. At this size, two diamonds of the same weight can be priced very differently.
Filter our loose lab grown diamonds or loose natural diamonds by 3ct to compare, or ask our gemmologists to shortlist stones for your budget.
Yes, and at this size we'd recommend it.
Book a free consultation at our Hatton Garden or Birmingham showroom and our gemmologists will prepare a selection of 3ct diamonds for you, with sample rings to try on so you can see the size on your hand.
You can also view diamonds live on camera in a virtual appointment.
Do you have additional questions? No problem, let us help you through the process