How Big Is a 1.5 Carat Emerald Cut Diamond?
About 7.5mm by 5.3mm. How ratio changes the look, a full emerald cut size chart, and the clarity grade this shape really needs.
A 1.5 carat emerald cut diamond typically measures around 7.5mm long by 5.3mm wide. On the hand it reads as a clearly substantial ring, noticeably longer than a round of similar weight, and it draws the eye along the finger rather than across it.
That is the short answer. Because emerald cuts vary in proportion more than most shapes, the longer answer is worth two minutes of your time.
Understanding the two numbers
An emerald cut is rectangular with cut-off corners, so it has a length and a width rather than a single diameter. Both matter.
The relationship between them is called the length-to-width ratio. Divide the length by the width and you get a number, usually between 1.30 and 1.60 for emerald cuts. A 7.5mm x 5.3mm stone has a ratio of about 1.42, which is the classic emerald cut proportion.
Carat, meanwhile, is weight rather than size: one carat is 0.2 grams. Two stones can both weigh 1.50ct and measure differently, because weight can be hidden in the depth below the setting.
How 1.5 carats changes with the ratio
This table shows roughly how the same 1.50ct of weight can be arranged. All are approximate, well-proportioned stones.
| Length-to-width ratio | Approximate measurements | How it reads |
|---|---|---|
| 1.30 (squarer) | 7.1mm x 5.5mm | Broader, chunkier, bolder |
| 1.42 (classic) | 7.5mm x 5.3mm | The balanced, timeless look |
| 1.55 (elongated) | 7.9mm x 5.1mm | Slim and elegant, very elongating |
The weight is identical in all three. What changes is how the stone sits on your finger. If you have shorter fingers, the elongated version flatters them. If you want maximum presence across the finger, the squarer version does more.
Emerald cut size chart by carat weight
Approximate measurements at the classic ratio, offered as guidance. The certificate for any individual stone is always the authority.
| Carat weight | Approximate size |
|---|---|
| 0.50ct | 5.5mm x 3.9mm |
| 0.75ct | 6.2mm x 4.4mm |
| 1.00ct | 7.0mm x 5.0mm |
| 1.25ct | 7.3mm x 5.2mm |
| 1.50ct | 7.5mm x 5.3mm |
| 2.00ct | 8.3mm x 5.9mm |
Notice how little difference there is between 1.25ct and 1.50ct in millimetres. This is the single most useful thing to know when budgeting: weight climbs faster than visible size, so buying slightly under a milestone weight gets you nearly the same look for less.
How a 1.5 carat emerald cut compares with other shapes
| Shape at 1.50ct | Approximate size | Visual impression |
|---|---|---|
| Round | 7.4mm across | Compact, maximum sparkle |
| Emerald | 7.5mm x 5.3mm | Long, calm, architectural |
| Oval | 8.8mm x 6.5mm | Largest face-up of these three |
| Marquise | 12.0mm x 6.0mm | Longest, most dramatic |
An emerald cut does look larger than a round of the same weight, but it is not the biggest-looking shape available. What it offers instead is that broad, mirror-like flash and a very clean, deliberate outline.
What 1.5 carats in an emerald cut demands of you
Size brings a responsibility with this particular shape. An emerald cut has a large, open flat top, which acts like a window into the stone. The bigger the window, the more you see.
Clarity. Clarity describes how few natural marks, called inclusions, a diamond contains. At 1.5 carats in an emerald cut, aim for VS2 or better. VS1 and above is safer still. On a round brilliant you could drop lower and get away with it; here you cannot.
Colour. Larger stones show warmth more readily. In white gold or platinum, choose a colourless or near-colourless grade. In yellow or rose gold, a slightly warmer stone looks perfectly at home.
Cut evenness. Look for straight, regular steps inside the stone and four evenly sized corners. Ask for a video of the actual stone if you cannot see it in person.
Every centre stone we supply comes with a free IGI certificate showing measurements, weight, colour and clarity, so none of this has to be guesswork.
What it costs
As general guidance rather than a quote: emerald cuts are less expensive per carat than round brilliants because cutting them wastes less rough. A 1.5 carat lab-grown emerald cut costs a fraction of a natural stone of comparable colour and clarity, which is why this is the shape where lab-grown makes the biggest practical difference. It lets you buy the clarity grade the shape really needs.
Our ready-made emerald cut rings use smaller centre stones, and their real prices, correct at the time of writing, are:
| Ring | Style | Price |
|---|---|---|
| Solitaire Emerald Cut Engagement Ring | Single stone, clean lines | £672 |
| Three Stone Emerald Cut Engagement Ring | Centre stone with two side stones | £1,017 |
| Hidden Halo Emerald Cut Engagement Ring | Hidden diamonds beneath the centre | £1,016 |
For a 1.5 carat centre stone specifically, that is a bespoke commission. There is no extra design cost for bespoke with us: you pay for the stone and the metal, and we design it with you free of charge.
Browse the emerald cut collection or the wider engagement rings range to see the shapes side by side.
Settings that flatter a 1.5 carat emerald cut
At this size the setting has two jobs: hold a substantial stone securely, and avoid cluttering an outline that is meant to look clean.
| Setting | Why it works at 1.5 carats |
|---|---|
| Solitaire | Nothing distracts from the shape. The purest and usually the least expensive choice |
| Hidden halo | Small diamonds sit under the centre stone, adding light from the side while the top view stays clean |
| Three stone | Two smaller stones extend the line along the finger and make the ring read wider |
| Bezel | A rim of metal around the stone; very secure, sits low, ideal for busy hands |
| East-west | Stone turned sideways across the finger; modern and it maximises apparent width |
A word on claws. Four claws is standard for an emerald cut and it looks clean, but at 1.5 carats ask for slightly heavier claws or a bezel if you wear your ring every day. The stone is not fragile, but the metal holding it does wear over years of use.
Band pairing
Emerald cuts sit flat, with straight edges, so a plain straight wedding band nests against them perfectly with no gap. This is one of the shape’s quiet advantages over pointed shapes, which usually need a curved or notched band to sit flush.
Frequently asked questions
How big is a 1.5 carat emerald cut diamond?
Approximately 7.5mm long by 5.3mm wide at the classic length-to-width ratio. A squarer stone of the same weight measures closer to 7.1mm x 5.5mm, and a more elongated one closer to 7.9mm x 5.1mm.
Does a 1.5 carat emerald cut look bigger than a 1.5 carat round?
It looks longer, which most people read as larger, but the round covers slightly more area in a compact circle. If pure face-up size is your goal, an oval of the same weight beats both.
What clarity do I need at this size?
VS2 as a floor and VS1 or better for real confidence. The open top of an emerald cut makes inclusions easy to see, and a 1.5 carat window is a large one.
Is a 1.5 carat emerald cut practical for daily wear?
Yes. Emerald cuts have cut-off corners instead of sharp points, so there is nothing fragile to chip. A slightly lower setting keeps a stone this size from catching on clothing.
Can you source a 1.5 carat emerald cut for me?
Yes. Tell us the ratio, clarity and metal you want and we will find the stone and hand-make the ring in solid gold or platinum at our North Harrow workshop in London.
A final suggestion
Cut a 7.5mm by 5.3mm rectangle from card and wear it taped to your finger for an hour. Charts and photographs both lie about size; your own hand does not.
Free insured UK delivery and 30-day returns apply to every piece, so if the size is not right when it arrives, nothing is lost.
More guides on this topic
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