When Would I Notice Size Differences in Carat Weights?

What carat size should I choose? Would I be able to notice a difference between 2 diamonds that are 0.3 mm apart? When would I start noticing size differences physically with diamonds from various carat weight brackets?

layout of different types of diamond shapes

If you are one of the people with these questions in mind, don’t worry, it’s very common. I get asked these questions frequently via emails and decided to create this blog post to answer them.

First things first, let’s address why people ask these questions. The underlying reason is always related to cost and when we are talking about thousands of dollars, I’m sure everybody wants to make a purchase that offers best value for money.

Diamond prices jump at every 10 points. For example, a 0.50 carat diamond would cost about 40% more than a 0.40 carat diamond of similar specifications. However, the real difference in size between these 2 stones is roughly 0.4mm. And if you pick up a ruler and look at the subdivisions, a 0.4mm difference might not be that big of a size difference.

how does 1 mm look like

Ruler showing 1mm markings

To help with visualization of different sizes, we’ve compiled a printable chart of real-life diamond sizes and their relative carat weights. Click here to check it out and download a copy in .pdf format.

The Key Question Is: Can You Tell The Differences?

Weird as it seems, people tend to notice the 0.4mm difference when comparing objects of smaller sizes. When comparing bigger objects, our brains seem to perceive the same difference as insignificant. Let me show you some examples to illustrate this…

size difference between .4 carat and .5 carat4.8mm – 5.2mm

Do you see the differences? Most people do when they compare a 0.40 carat diamond against a 0.50 carat diamond.

size difference between 1.50carat and 1.75 carat

7.4mm – 7.8mm

In contrast, the same physical difference between a 1.50 carat diamond and 1.75 carat diamond isn’t readily detected because of the way our brain works.

Here Are a Few Other Examples to Check Out…


size difference between 0.9 carat and 1.0 carat

6.2mm – 6.5mm

Also, what happens if I pull the same diamonds further apart from each other?


further apart



comparison at a distance


Do you realize it is harder to notice size difference now? In real life, most people casually observe diamonds from a distance and it isn’t easy for them to pick up minute differences.

Now, most people buy diamonds within the 0.50 – 0.75 carat ranges. If you do a comparison using the image below, I think it is pretty clear that you would notice a difference.

size difference between carats of 0.50 and 0.755.2 mm – 5.8mm

Ultimately, Your Opinion Is What Matters Most!

So, what do you think? Perception is more of a subjective matter than an objective one. Some people see differences in sizes easily and some don’t. It is the same with diamond colors where individuals can see clear differences between F and G color diamonds whereas the majority of us don’t.

I know of people who are psychologically affected by the size of the diamond in their minds. Even if they are wearing a 0.92 carat diamond, in their mind, it is never good enough unless it is a 1 carat diamond.

Go for a carat size that’s “mind-clean” and affordable to your wallet. After all, diamonds are purchases which are meant to be enjoyed instead of being something that constantly frets you at the back of your mind.

If you are looking for a diamond that is cut to the best standards and optimal light performance, I recommend checking out Whiteflash and Brian Gavin. Their signature diamonds look spectacular in real life and represent the top 1% of well-cut diamonds in the market.

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  1. teresa-
    August 25, 2012 at 2:13 am

    what would be a fair price for a diamond with 0.53 carats, F color and VS2 clarity?

  2. Paul-
    August 25, 2012 at 9:18 am

    Unfortunately there is no way to tell with the limited information that you had posted.

    If possible, please include the shape of the stone and grading report in order for me to give you accurate advice.


  3. Ludmila Pechalová-
    September 14, 2012 at 5:01 am

    I am actually considering a split shank design for my new ring project. Are there any tips or advice that you would offer for one that would enhance the size of the center stone?

  4. Paul-
    September 16, 2012 at 10:32 am

    A halo setting would help greatly when done right.

    *edited comment for updates in blog*

    I had made a blog post on how different ring designs can help enhance the physical size of the center stone. It’s well worth your time checking it out here:


  5. Nicoline J. Karlsen-
    October 4, 2012 at 1:03 am

    Does this look like a good buy?

    Pear: 1.21 carat, 62% depth, 59% table, F color and VVS2 clarity.

    Thanks for the awesome website and your opinion on this stone…

  6. Paul-
    October 5, 2012 at 11:43 am

    Hi Nicoline,

    On paper, it seems like an OK choice. However, I won’t recommend buying a pear shaped based purely on paper. There are some aspects like bowties and light performance factors that a grading report won’t tell you.

    Please read the following links for more details:


    Feel free to bump me an email if you have further questions.

  7. Modi-
    April 24, 2016 at 12:46 pm


    I was looking into diamonds and found this:
    Round cut, vvs2, g, very good cut, 0.92 carat. What’s a good ballpark price for a diamond with that specifications ?

  8. Paul Gian-
    April 24, 2016 at 3:21 pm


    I will not pay a single cent for a diamond that’s poorly cut. And yes, Very Good is simply mediocre.

  9. Julia Santos-
    June 23, 2016 at 6:17 am

    Hello there. Should I get .80 round ideal cut, f , vvs2 or 1.18 round ideal cut, I, sl1 for $1,200 more?

  10. Paul Gian-
    June 23, 2016 at 6:26 am

    Depends on what your priorities are. Read this: http://beyond4cs.com/buying-diamonds-blind/

  11. Ken-
    August 14, 2016 at 10:30 am

    Am looking at 2 Round Brilliant Diamonds, one is 1.01 and another is 1.06 carats. Both are VVS1, D Colour, XXX cut/clarity etc. Help with prices pls? 🙂

  12. Paul Gian-
    August 14, 2016 at 3:34 pm

    There’s a link in the navigation tab under “Home” that explains prices in details.

  13. Stephen-
    October 8, 2016 at 12:11 pm

    Hi would you go for a .40 round brilliant Colour F Internaly flawless cut excellent or
    .50 colour H VS1 very good cut ??

  14. Paul Gian-
    October 8, 2016 at 2:56 pm

    Neither. The flawless clarity is a waste of money. The very good cut on the H diamond is just a turn off.

  15. Michelle-
    December 23, 2016 at 10:06 pm

    Hi Paul,
    I’m glad I found your site. Just curious regarding your answer to ” Hi would you go for a .40 round brilliant Colour F Internaly flawless cut excellent or .50 colour H VS1 very good cut ??”. Why do you say ” flawless clarity is a waste of money” ?

    I m considering buying an round, F, IF, excellent cut/ symmetry/ polish.

  16. Paul Gian-
    December 26, 2016 at 3:44 pm

    In reality, you won’t be able to see differences with the naked eyes between a VS diamond and an IF diamond. That’s why I think it is a waste of money unless you are looking for symbolic reasons for an internally flawless stone.

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