Round Brilliant cut diamonds in various sizes and carat weights
Round Brilliant cut diamonds in various sizes and carat weights

Diamond Size Chart: Your Guide To Carats And Size

Angelica Frey | February 08, 2023

When it’s time for you to buy a diamond, you first have to educate yourself on the 4Cs, namely cut, color, clarity, and carat. These will give you a good degree of information on the appearance of a diamond: cut will inform you on the proportion of its dimensions, color will indicate the degree of coloring present in the diamond; clarity will notify on the presence of inclusions, and carat will indicate the diamond’s weight. The 4Cs won’t actually reveal the diamond’s actual size, meaning its dimensions and the way it appears on a finger.

Read on to learn more or book an appointment with our diamond experts for personalized guidance.

What Are The Sizes Of Diamonds?

Diamond size refers primarily to the stone’s measurements or dimensions. Most often, we think of diamond size as referring to what a diamond looks like from above, so it takes its length and width into account. Diamonds also have depth, which is distributed in the pavilion, which refers to the lower part of the diamond, from the bottom of the girdle to its culet.

How Do We Measure The Size Of A Diamond?

The word carat is often used in association with a diamond’s size as a whole. Truth is, the carat is the unit of measurement of a diamond’s mass. One carat is 0.2 grams, but in terms of dimensions, it gives no indication of actual measurements. Ways to measure a diamond’s size include length-to-width ratio, the weight distribution in the crown and the pavilion, and the surface area of a diamond’s table. In addition a diamond’s shape and its cut grade also determine its size: a diamond that has a higher cut grade can appear larger than another diamond that technically weighs more and has a higher carat number, but a poorer cut grade.

What Does Carat Have To Do With Diamond Size?

In terms of diamond measurements, there is no 1:1 correlation between carat and size. For example, a 2 carat diamond is twice as large as a 1 carat diamond, but, visually, it will only appear to be 50% larger. A diamond’s size consists of its measurements in width, length, and depth, and is directly correlated to its appearance, and the way it will look on your finger; carats refer to the diamond’s weight, and one carat corresponds to 0.2 grams.

What Is The Size Of A 1 Carat Diamond?

While a diamond’s size and its carat weight are two separate concepts, diamond-size charts can show correspondences between mms and carats. In the case of a 1 carat diamond, which is perhaps the most popular weight, a 1 carat Round Brilliant diamond will measure around 6.5mm in diameter, while an Asscher or a Princess cut will measure 5.5mm in length and width. Elongated cuts like Marquise, Oval, and Pear face up larger, as their table occupies a larger surface area: a 1 carat Marquise measures 10mm by 5 mm; a 1 carat Oval diamond 7.7 mm by 5.7mm; similarly, a Pear shaped diamond 7.7 by 5.7 mm.

What Is A Good Diamond Size For An Engagement Ring?

When choosing your engagement ring, several factors come into play, including the wearer’s style, aesthetic, and the budget that will be invested in the purchase. Once you determine your budget, you have to choose a diamond shape, a style, and a setting. Once you establish a budget, the diamond size of your choice entirely depends on personal style preferences and cultural factors: some prefer smaller center diamonds with very high grading, others place great importance on the size of the stone. One good way to make an initial decision is by seeing a diamond on your actual hand: booking an appointment with one of our experts allows you to see how different shapes and sizes match with your hand.

What Diamond Size Should You Choose For Earrings?

Diamonds are not limited to engagement rings. Earrings and necklaces are a great way to showcase the beauty of a stone while also framing your face.

In the case of earrings, diamond studs are among the most versatile pieces of jewelry that are timeless, modern, and elegant regardless of the context you’re wearing them in, and the size of a diamond depends on your own comfort level and lifestyle. Diamonds that measure 4 or 5 mm in diameter (so 0.25 to 0.5 ct) make the perfect day-to-night studs, and if you want to give the illusion of a bigger diameter or adorn them in a sleek way, a bezel setting can make the area and circumference of your diamond appear larger while also firmly securing it. Diamond studs above 6.5 mm in diameter (so over 1 carat) retain their timeless elegance while also conjuring cinematic opulence.

How Will A Diamond Of A Certain Size Look On My Finger?

The way a diamond will look on a finger depends both on its own size and shape and on the size and shape of the hand and finger of the wearer. A deciding factor is determining how much of the finger’s width you want the diamond to cover.

You first need to know your (or your significant other’s) exact ring size, which mostly goes from size 3 (14.1 millimeters) to size 14 (23.1 millimeters). The average size is 6, with a width of 16.5 mm, with 6 being the average size.

Whether you want your ring to complement your hand shape or elegantly elongate it, understanding how a diamond shape works on a hand is an essential step in the purchase of a diamond. Jewelry experts say that each extra millimeter is like a mile, so even comparing diamonds that are only half a mm apart in length or diameter will be a completely different experience. Our experts can let you try out different sizes and shapes for yourself, so you can see firsthand the way they complement your hand.

Close-up of Round Brilliant cut diamond

Sizes Of Round Brilliant Cut Diamonds On Finger

The Round Brilliant cut diamond is a universal and timeless shape that works on a wide variety of hands.

If we operate using size 6 as a standard, then a 1 carat Round Brilliant diamond, which measures 6.5mm in diameter will cover around 40% of the finger’s width. A 1.5 carat diamond, which measures 7.4 mm in diameter, will cover circa 45% of your finger’s width; a 2-carat diamond has a width of 8.15mm, which means that it takes up 50% of the finger’s width. At 9.35mm in diameter, a 3 carat diamond will cover more than 55% of the finger’s width.

Close-up of Oval cut diamond

Sizes of Oval Cut Diamonds On Finger

Oval cut diamonds are ideal for shorter and/or larger fingers as they have a lengthening effect.

In fact, A 1-carat oval-cut diamond measures 7.7mm in length by 5.7 mm in width, a 1.5 carat Oval is 8.5 by 6.5mm while a 2 carat Oval diamond measures 9 mm in length by 7 mm in width. For comparison purposes, a 3 carat Round brilliant cut diamond measures a little over 9 mm in diameter, so a 2 carat Oval diamond is visually quite similar to a 3 carat Round Brilliant, but far more slenderizing. As for the measurements of a 3 carat Oval diamond, it’s, on average 12 mm by 8 mm, and 12 mm is the diameter of a 6.84 carat Round Brilliant diamond.

Close-up of Emerald cut diamond

Sizes Of Emerald Cut Diamonds On Finger

Much like the Oval, the Emerald cut diamond does, with its elongated shape, give the illusion of longer and slender fingers. A 1 carat Emerald diamond measures 7 mm by 5 mm, a 1.5 carat Emerald is 7.5 long and 5.5 mm wide, a 2 carat is 8.5 by 6.5 mm while a 3 carat measures, on average, 10 mm by 7.5 mm. Compared to the Oval, which has the same types of facets as the Round Brilliant, the Emerald diamond, with its step facets and its signature hall-of-mirrors effect has a more subdued brilliance.

Close-up of Princess cut diamond

A Note On Square Diamonds

Square diamond shapes like the Princess cut, the Radiant cut, the Cushion cut and the Asscher cut face up small: at 1 carat, they all measure 5.5 mm, and even as you go up in size, they appear noticeably smaller than a Round Brilliant cut: their strength lies in their brilliance and the artful arrangement of their facets. These rings suit slender fingers or smaller hands best.

Diamond Size Chart

Angelica Frey | February 08, 2023

Your guide to understanding VRAI created diamond sizes. Because each stone is unique, we've added both minimum and maximum measurements for accuracy.

Diamond ShapeCarat WeightMinimum MmMaximum Mm
Oval0.56.58 x 4.456.78 x 4.65
Oval18.29 x 5.618.49 x 5.81
Oval1.59.50 x 6.439.70 x 6,63
Oval210.47 x 7.0910.67 x 7.29
Oval311.98 x 8.1112.18 x 8.31
Oval413.19 x 8.9413.39 x 9.14
Oval514.21 x 9.6414.41 x 9.84
Pear0.57.25 x 4.357.45 x 4.55
Pear19.14 x 5.509.34 x 5.70
Pear1.510.45 x 6.3010.65 x 6.50
Pear211.53 x 6.9511.73 x 7.15
Pear313.19 7.9513.39 x 8.15
Pear414.53 x 8.7614.73 x 8.96
Pear515.65 x 9.4515.85 x 9.65
Emerald0.55.69 x 3.895.89 x 4.09
Emerald17.15 x 4.907.35 x 5.10
Emerald1.58.20 x 5.658.40 x 5.85
Emerald29.04 x 6.209.24 x 6.40
Emerald310.36 x 7.1110.56 x 7.31
Emerald411.41 x 7.8411.61 x 8.04
Emerald512.30 x 8.4512.50 x 8.65
Cushion0.54.90 x 4.655.10 x 4.85
Cushion16.17 x 5.876.37 x 6.07
Cushion1.57.09 x 6.747.29 x 6.94
Cushion27.8 x 7.428 x 7.62
Cushion38.95 x 8.59.15 x 8.7
Cushion49.85 x 9.3710.05 x 9.57
Cushion510.62 x 10.1110.82 x 10.31
Marquise0.58.25 x 3.988.45 x 4.18
Marquise110.4 x 5.0310.6 x 5.23
Marquise1.511.93 x 5.7712.13 x 5.97
Marquise213.13 x 6.3513.33 x 6.55
Marquise315.04 x 7.2915.24 x 7.49
Marquise416.56 x 8.0316.76 x 8.23
Marquise517.85 x 8.6518.05 x 8.85
Radiant0.55.25 x 4.085.45 x 4.28
Radiant16.6 x 5.176.8 x 5.37
Radiant1.57.6 x 5.917.8 x 6.11
Radiant28.35 x 6.538.55 x 6.73
Radiant39.55 x 7.489.75 x 7.68
Radiant410.55 x 8.2510.75 x 8.45
Radiant511.35 x 8.8911.55 x 9.09

Book An Appointment With Our Diamond Experts

In a context where even a 0.5 mm makes quite a lot of difference, and where a diamond’s shape plays an important role in the appearance of your finger, talking to our experts in our showrooms will allow you to try on different sizes and shapes to see what works best for you. Book an appointment today for more personalized guidance and in-depth diamond education.