3.4 vs 3.8 carat - Visual difference?

[aptp]

I am looking for a round diamond as close to 4 carats as possible, but have noticed that there are very few ideal cut diamonds in the 3.6+ - 3.99 range. I am thinking about going for something below 3.5 carats instead (more ideal cut inventory available in this weight) but wonder if I will regret this decision. Is there a visible visual difference with a difference of about 0.3-0.4c in this size (eg. 3.4 v 3.8c round brilliant)? Or is the difference negligible to the untrained eye?

 

[rockysalamander]

Size 6.5

 

[scarsmum]

The difference is approximately .5 of a millimetre. Do two paper cut outs, one at 9.5 mm and one at 10mm then compare.

 

[Allisonfaye]

You should look at and compare the size of the diamond. Look at the certs. It's on there. If the smaller one is not as deep as the larger one, you might be seeing a very slight difference and vice versa.