When shopping for a diamond engagement ring, one of the first questions you need to ask yourself is how big the diamond should be. Diamonds are available in various sizes and carat weights, from 0.20 carats to more than 10 carats.
In this article, I’ll talk about how big is too big for a diamond engagement ring. I’ll also go into detail about understanding the differences between a diamond’s carat weight and actual size.
How Big Is Too Big for a Diamond Engagement Ring?
So, you’ve finally decided to buy a diamond engagement ring for that special someone. Or maybe you have the opportunity to choose one for yourself. Well, let me tell you. Picking one diamond ring that you’ll be wearing for the rest of your life is not easy.
Before making your final decision, there are four quality factors you must consider. These are the “four Cs” – color, clarity, cut, and carat weight. Most people only focus on the diamond’s carat weight, while the other Cs are usually seen as secondary. If you have the budget for a bigger diamond and the go big or go home approach, you can choose between various diamonds with 3, 4, 5, or more carats.
Just because you can afford a huge rock, doesn’t mean you should get one. Let me explain. A diamond with a particular carat weight will look flattering on thin and long fingers, but it can look bad on short and thick fingers, or vice versa. This is why you have to ask yourself how big is too big for a diamond engagement ring before making the purchase.
Understanding Carat Size

Before we get into how big is too big for a diamond engagement ring, let’s talk about carat weight.
A carat is a unit of measurement that refers to how many grams a diamond weighs. A 1-carat diamond weighs 1/5 of a gram, which is 0.20 grams or 200 milligrams. A 5-carat diamond weighs approximately 1 gram. If you think about it, that doesn’t sound like a lot, does it?
When a diamond is first cut, the main goal is to end up with as many carats as possible. Large natural diamonds are more expensive and valuable because they’re so rare. Conversely, smaller diamonds are more readily available on the market, which is why they’re more affordable.
That’s why we have diamonds with different carat weights, the average being 1 carat. However, a 1-carat diamond can come in different sizes. For example, a 1-carat diamond can be 6.5 mm in diameter, but it can also be 7.7 mm wide. That’s because a diamond’s carat weight and size are not the same thing.
Carat Size to Finger Size Ratio

To truly understand the difference between a diamond’s carat weight and size, we have to talk about ring sizes first. A ring size or a finger size refers to a ring’s diameter. Think of it as shoe sizes. In the U.S., jewelers use a scale from 3 to 13.5. Men’s ring sizes vary from 8 to 14, while women’s sizes go from 3 to 9. The average women’s ring size is 6.5, which is 17 mm in diameter.
Now, let’s go back to diamond sizes. Like I said before, a diamond’s carat weight doesn’t determine its size. A diamond’s size is measured in millimeters, and it refers to the diamond’s diameter. What actually determines a diamond’s size is its cut.
As you may already know, diamonds are available in different cuts, including the princess, round, emerald, radiant, heart, pear, oval, marquise, and more. Some diamonds are simply polished and faceted differently, making them larger than others. For example, a round-cut 1-carat diamond measures 6.5 mm in diameter. An oval-cut 1-carat diamond is 7.7 mm wide. This happens because some diamonds carry their weight in height, while others carry their weight in depth.
If you want to know how big is too big for a diamond engagement ring, you need to calculate how much space the diamond will take on your finger. For instance, assuming you wear the average ring size (6.5), a round-cut 1-carat diamond would take up 38.2% of the finger’s width, while a round-cut 3-carat diamond would cover 55.3%.
If you want to know more about the carat size to finger size ratio, this Estate Diamond Jewelry article explains this topic in detail.
World Records for Largest Diamonds and Rings

When shopping for a diamond engagement ring, you’ll most likely come across diamonds with 1, 2, 3, or 4 carats. Even a 1-carat diamond can cost more than $10,000, depending on its quality. Naturally, the prices go up for multi-carat diamonds. You might be surprised, but some of the biggest diamonds in the world weigh hundreds of carats.
The Cullinan Diamond holds first place as the biggest rough diamond ever discovered. In its uncut state, the diamond weighed 3,106 carats. It was later cut into several large diamonds, the biggest one weighing 530.40 carats.
Another giant diamond is the Lesedi La Rona, which was recently found (2015) in a mine in Botswana. Before the cutting process, the diamond weighed an astonishing 1,109 carats, but now it has 302.37 carats. The Lesedi La Rona has a square emerald cut, and it’s the largest square emerald-cut diamond in the world.
When it comes to colored diamonds, the Incomparable Diamond is definitely worth mentioning. When it was found in the Democratic Republic of the Congo, the diamond weighed 890 carats. Today, it weighs 407.38 carats, and it was made into a necklace. It broke the world record for the most expensive necklace, with a whopping $55 million price tag.
The biggest diamond ring in the world is set with more than 24,000 diamonds. A jeweler in India is responsible for this creation, breaking the Guinness World Record for most diamonds set in one ring. The ring is called “Touch of Ami,” and it’s so big, it covers most of the wearer’s hand.
How Small Is Too Small for a Diamond Engagement Ring?

Now that we’ve discussed how big is too big for a diamond engagement ring, let’s talk about the other end of the size spectrum.
The smallest engagement rings have diamonds of 0.20, 0.30, and 0.40 carats. They come in various cuts and settings. Not only are they far more affordable than larger diamonds, but they can be quite stylish and beautiful as well. Many brides-to-be don’t find the diamond’s size as important as other factors.
To figure out how small is too small for a diamond engagement ring, we would have to go back to the carat size to finger size ratio. If you have small hands or, let’s say, a 4 or 4.5 ring size, a smaller diamond would look more flattering on your finger. A large 3- or 4-carat diamond would look overbearing on slim and small fingers.
If you’re worried about the diamond being too small, the safest options are 0.50-carat and 1-carat diamond rings. A round-cut 1-carat diamond ring is universally flattering on most finger shapes and lengths.
Talk to a Jewelry Expert
Choosing the size of a diamond engagement ring can be a daunting task. You don’t want the diamond to be too small, but you also have to be careful about diamonds that are too big for you. If you’re still wondering how big is too big for a diamond engagement ring, fill out the form below and I’ll give you advice on the perfect diamond size for you.