Diamond Size Chart Millimeter (MM) to Carat (2023)

Diamond Chart Sizes…

The best way to measure diamondsis in millimeter. Since diamonds are purchased in carat weight (a standard unitof measurement for diamonds), it is helpful to also measure diamonds inmillimeters to determine its surface size as well as ratios such as length-to-widthratios in fancy shape stones in order to choose the best diamond for rightbudget.

Diamond Size Chart (Approximate Carat to Millimeter)…

Are you interested in knowing thesize of a diamond in millimeter based-off its carat weight?

You can use thediamond chart below to help you understand the millimeter (mm) size of roundcut diamonds.

Diamond Size Chart Millimeter (MM) to Carat (2)

The RoundDiamond Sizes

Round MM SizeRound Carat Weight
0.8 mm.0.0025 ct.
1 mm.0.005 ct.
1.12 mm.0.0067 ct.
1.15 mm.0.0075 ct.
1.25 mm.0.01 ct.
1.3mm.0.01 ct.
1.5mm.0.015 ct.
1.75mm.0.02 ct.
1.8mm.0.025 ct.
2mm.0.03 ct.
2.225mm.0.04 ct.
2.5mm0.06 ct.
2.75mm.0.08 ct.
3mm.0.11 ct.
3.25mm.0.14 ct.
3.5mm.0.17 ct.
3.75mm.0.21 ct.
4mm.0.25 ct.
4.25mm.0.28 ct.
4.5mm.0.36 ct.
4.75mm.0.44 ct.
5mm.0.50 ct.
5.25mm.0.56 ct.
5.5mm.0.66 ct.
5.75mm.0.75 ct.
6mm.0.84 ct.
6.25mm.0.93 ct.
6.5mm.1.00 ct.
6.8mm.1.25 ct.
Round MM SizeRound Carat Weight
7 mm.1.30 ct.
7.3 mm.1.50 ct.
7.5 mm.1.67 ct.
7.75 mm.1.75 ct.
8 mm.2.00 ct.
8.25 mm.2.11 ct.
8.5mm.2.43 ct.
8.7 mm.2.50 ct.
9 mm.2.75 ct.
9.1 mm.3.00 ct.
9.5 mm.3.35 ct.
9.75 mm.3.61 ct.
10 mm.3.87 ct.
10.25 mm.4.16 ct.
10.5 mm.4.41 ct.
10.75 mm.4.57 ct.
11 mm.4.91 ct.
11.25 mm.5.49 ct.
11.5 mm.5.85 ct.
12 mm.6.84 ct.
12.25 mm.7.26 ct.
12.5 mm.7.36 ct.
12.75 mm.7.52 ct.
13 mm.8.51 ct.
13.5 mm.9.53 ct.
14 mm.10.49 ct.
15 mm.12.89 ct.
16 mm.16.06 ct.

Reasons Why Diamond Millimeter measurements are important…

The measurement of a diamondmillimeter will inform you about its actual size. This is because diamondweighing similar carat weight can have different faceting and maybe be largerthan the equivalent carat weight. In case you are interested in a diamond thathas a larger surface, it is important that you consider getting a diamond thatis well cut. Shapes such as pear, emerald and oval are known to have a largerlook compared to their round counterparts; overall round cut is stillconsidered to have a large surface size though.

If you are buying a diamond thatis already set in an existing setting, measuring the millimeter of the diamond willhelp you estimate the carat weight of the diamond. However, it may be tricky toget it measured accurately. It is best to seek the advice of a local jeweler insuch cases (note: local jewelers are notorious for misleading consumers, somake sure you consult a reliable jeweler).

It is also important to considermillimeter measurements when buying non-round diamond shapes such as emeraldand cushion. This is because the measurements of the millimeter will reveal ifthe diamond rectangular or square, also if it is too shallow or deep (big tableor large depth).

There will be more rectangular measurementsfor emerald cut diamonds, and the square ones are referred to as asscher cuts.

When buying diamonds, themillimeter measurements and carat weight can be found on the grading reports.


(Video) Round shape diamond size comparison with MM size 1ct untill 3ct

One popular term you will alwayshear from a wholesaler or atrader is pointers. A pointer is equivalent to carat weights. One pointer refersto 0.01 carat diamond. This term is used when we describe melees in the 1-2mmrange (small accent diamonds found on jewelry and engagement rings).

With each diamond being unique, itis important that you teach yourself on the average millimeter sizes of variouscarat weight diamonds to make it possible to find the right option. Read thegrading reports of the diamonds for best ways to measure their millimeters.

The Round Diamond Size...

This is considered by many as oneof the most popular diamond shape. Round brilliant cut diamonds areaesthetically pleasing and versatile. At a reasonable finish and proportionalcut, the brilliant cut diamond which is 57-58 faceted rounds is capable ofoutshining other types of diamond in the market. The round diamonds size doesaffect the saturation of the stone color, light and clarity performance.

The Princess Diamond Size...

Please refer to our princess cutdiamonds chart guide for detailed information.

The closest rivals to the roundbrilliant cut are the princess cut diamonds. This excellent square shape offerssharp and beautiful alternative to the round cut diamonds. The princess cutdiamond does cost less than the round cut.

Light performance is one of themost variable features of the princess cut diamond. A princess cut is capableof having an immaculate sparkle in any size. However, as each facet shinebecomes more brilliant, the larger the diamond will be.

The Cushion Diamond Size...

Please refer to our article on cushion cutdiamonds for detailed assessment.

Cushion cut diamond compromisesthe round cut diamond and shapes with sharp edges and corners. This cushiondiamond is known to be of vintage style although it ranks among the top fivepopular diamond cuts. This diamond is also known to be prominent in jewelry puton by celebrities and royalty.

With cushion cut modernization,culets detracted from the unique cushion diamond beauty have been reduced toratios unnoticeable and the appearance of the facet has grown more delicate andsmaller. The cushion cut diamonds do show more clarity and faceting with theirincreasing size.

The Emerald Diamond Size...

Please refer to our guide on emerald cutdiamonds for detailed assessment.

This diamond does resemble gemswith rectangular shapes. Just like the cushion cut diamonds, the Emeralddiamond corners are also soft and rounded. It is known to be among the mostcommon vintage style jewelry diamond cuts and for pairing with synthetic or realemeralds. Due to the elongated emerald cut diamond, they at times lose someshine.

(Video) Measuring a Diamond’s Carat Weight is Easier than you think | How to Convert Millimeters to Carats

The Oval Diamond Size...

Please refer to our article on oval cut diamondsfor detailed assessment.

This is one of the most popularchoices for females who like non mainstream and unique jewelry. Just like theemerald, the oval cut diamonds do have slimming effect and elongated shape ontheir hand. When you cut an oval diamondto the right depth proportions, it will have a similar brilliance to the roundcut diamonds. They do get brighter as the size of the carat increases.

The Pear Diamond Size...

Please refer to our article on pear cut diamondsfor detailed assessment.

Pear diamond also referred to as the teardrop shaped can be compared tothe oval diamonds on uniqueness scale. However, you can use this cut to createthe nontraditional and one of kind engagement rings. The diamonds are usuallyused in solitaire necklaces and earrings.

Color is known to be an excellent feature of the pear cut diamonds.However, the tip is known to lose some of the color in its smaller sized caratsalthough the body and bottom of the diamond do not.

The Marquise Diamond Size...

Please refer to our guide on marquise cutdiamonds for detailed assessment and analysis.

Marquise also referred to as the football shape is a common stone shapein the antique and vintage jewelry. It is another style of diamond that lookslarger when compared to other shapes and cuts. However, the facets counts canchange at once depending on the size which ranges anywhere from 50-60 facets.

The Asscher Diamond Size...

Please refer our detailed guide for assessing asscher cutdiamonds.

In all the finished and correctlycut Asscher diamond is the windmill design. This pattern comes by as a resultof step cut that is similar to the emerald diamonds. However, the step cut doesnot diminish in smaller Asscher diamonds as the patterns do become morecompact.

Radiant Diamond Size...

Please analyze and examine the details of radiant cut diamondsin our detailed guide…

(Video) CapeDiamonds Diamond size chart

It is a combination of both theAsscher, round and emerald cut diamonds. It goes by many names and it does makeone of the modern stones available in the market. However, characteristicsnever vary from a single size carat of radiant diamond to another.

Effects of Carat on the Price…

Please read our detailed articleon diamond price factors.

Since diamonds are priced inrelation to per carat basis, carat does have the biggest impact on the price.As the carat increases, so is its price. For instance, the 2 carat is not the 1carat double price because it is getting harder to get rough materials that arebetter enough to be cut into one large and single sized diamond.

Here is how the price will beaffected by the carat. All these diamonds have the excellent cut, VS2 clarityand H color to make comparison easier. However, the only difference is in thesize of the carat.

We do have magic numbers forcarat weight in thediamond industry. There are the 2.0, 1.5, 1.0, 0.75, 0.5and thereafter every carat half. It is the point at which there is great jumpin price. The price doubles at each point. There is clarity, cut and color which also play a role in determiningthe final price of the diamond.

Reasons Why You Should Prioritize Carat…

Definitely, you are aspiring tohit a certain number of carats. However, this should never be your only toppriority. You should instead think of focusing on getting the best cut. Having a great cut will make the diamond belivelier and can hide mask color and flaws and can also make the diamondlarger.

The left diamond is good cut andis 1.00 carat. It has a 6.2x6.3mmsurface area.

The right diamond is of excellentcut and weighs 0.92 carats with a surface area of 6.2x6.2mm.

Despite the two diamonds havingdifferent sizes of carat, they all have the same surface area. However, due tothe poorer cut of the initial one, up to 10% of the weight of carat is wasted.

Although the left diamond hits 1carat, it will never sparkle as much compared to the one on the right. For $500 lesser, the diamond with 0.92 caratfound on the right is better to purchase. This explains why one should neverprioritize weight of carat. Weight will never do much when you cannot even seeit and not even a single person will be interested in a lackluster diamond.

Choosing Diamond Size…

When you are looking for adiamond to buy, it is important that you always consider the weight of thecarat and understand millimeter size do vary for diamonds having similarweight. Since diamonds are precisely cut using machine, there can at times be slightvariations which can be caused by inclusions or other types of factors in thediamond.

The millimeter size can also beaffected by the depth of the diamond from face up view.

(Video) How to Calculate the Diamond Weight of your Jewelry Design? MM Size to Carat Weight for Estimation

In case you are concerned aboutthe sizing of the diamond, you need to remember that you can always contact agemologist concerning the best proportionsfor that particular shape. There are diamonds which are lowly priced thanexpected since their millimeter size is less than the right size. However, youwill have to consider the size of the diamond against factors like color andclarity. It is very productive to make a greater compromise in order to get alarger diamond.

Factors to consider when you Lack larger budget…

It is a fact that very fewindividuals are in a position to afford the 2 carat stone. There are quite ahuge number of people who struggle to get to the 1 carat mark. Below are someof the options you can consider when on a budget.

Consider using the settings to make the diamond look bigger…

Halo is one of the most commonsettings that contain small diamonds rings around the diamond center. Thesetting offers a serious bling that makes it appear as if the diamond locatedat the center is huge. A thing pave band is another great setting you can gowith. You will make the center stone pop when you set the main diamond that iswithin the small diamonds band. Keep inmind that both the larger diamond center and the thinner band will appear.

In case you are not sure of thetype of shape and style to select, you can always visit James Allen inspirationGallery or the Blue Nile before purchasing an engagement ring The feature willmake it possible for you to view the real images of people that have boughtrings in the past and help you in deciding the best style for you. The side stone or 3 stone is the worst settingthat tries making the diamond appear larger. The hick and heavy bands are neverof great help to the smaller diamonds.

Get a diamond that is slightly below the magic numbers…

Magic numbers do vary with arange of 0.5 carats. The diamond sellers are capable of fetching more withthese weights. In case you go below the magic number, you can always get adiamond for as much as 25% low.

Factor in the Fancy ShapedDiamond

Going for shape besides round isone of the great suggestions. The fancy cut diamonds will not only appearlarger, they are also cheaper compared to the round cuts. They are also uniqueand appealing to females who like standing out in crowds.

Get lower in clarity and color…

It is already clear that you should never sacrifice the cut. However,you can get lower in clarity and color in order to reduce the price. Providedthe cut is excellent, it does matter if there are other flaws, the diamond willalways appear brilliant.

It is recommended that a minimum VS2 clarity and H color although youcan get lower to a J color when you don’t mind a warmer appearance. There areamazing SI2 diamonds when you get one which is eye clean.


Carat is known to be one of the most difficult things to advice on dueto its personal choice. We do understand if there is a goal one wants to hit.We do suggest that you do not make it your top priority at the expense of therings overall beauty.

(Video) Round shape diamond size comparison with MM size (0.50ct to 0.90cts)

It is important that one concentrates on getting the best cut that iswithin their budget. Any diamond that is well cut will beautifully sparkle andit is much better for one to have a great diamond instead of just a big one.


1. All About Diamonds : Determine the Carat of a Diamonds
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2. How to measure gemstone/diamond size
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3. Does Size Matter? Part 1: Carats vs. Millimeters of Moissanite & Diamond
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4. Diamond Carat Size Comparison with Pricing for Round Diamonds .50 -.75 to 1 carat- to a 3 carat
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5. Gem Size Comparisons from .5 to 6 Carats
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6. Carat Weight vs. Millimeter Size: How to pick the perfect gemstone!
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