Does each new Horcrux take half of Voldemort's remaining soul, thus taking a smaller piece each time?

Question

When you commit a murder and create a Horcrux, you split your soul. It’s been talked a lot about Voldemort splitting his soul in 7/8 parts. But I think his remaining soul was not 1/7 or 1/8 but far more weaker than that because he did not create all Horcruxes at once.

When he created his first Horcrux, his soul was split into 50-50 (diary). But when the second Horcrux was created, it was created by Voldemort only and the first Horcrux soul should have remained intact. Hence it would have been a 25-25 split of Voldemort's main soul. And so on for every split.

Am I right?

Answer 1

You're (probably) right that his remaining soul wasn't 1/8th of what he started with, but it also wouldn't have been 0.0078% of his total after being split that many times. There's simply no evidence that explicitly states it's a 50/50 split of the soul. The words most commonly used are "piece" and "fragment", and while they don't explicitly indicate a specific size, fragment by definition suggests that it's a portion of the soul much smaller than the whole.

"Tell him that on the night Lord Voldemort tried to kill him, when Lily cast her own life between them as a shield, the Killing Curse rebounded upon Lord Voldemort, and a fragment of Voldemort’s soul was blasted apart from the whole, and latched itself onto the only living soul left in that collapsed building. Part of Lord Voldemort lives inside Harry, and it is that which gives him the power of speech with snakes, and a connection with Lord Voldemort’s mind that he has never understood. And while that fragment of soul, unmissed by Voldemort, remains attached to and protected by Harry, Lord Voldemort cannot die."
_{Chapter 24 - The Prince's Tale, Deathly Hallows}

Six true Horcruxes (diary, ring, locket, cup, diadem, Nagini) created intentionally, then the fragment of soul that was inadvertently attached to Harry when Avada Kedavra backfired, means there would have been (at least) eight separate, but not equal sized, parts of Voldemort's soul.

Answer 2

There’s no indication that making a Horcrux splits the soul in half.

It’s unclear exactly how much of a soul the Dark Lord had left when he was done making Horcruxes (and accidentally left a piece in Harry). There’s nothing that states what percentage of the soul is split off to make a Horcrux - it’s just described as a piece or a portion.

“Killing rips the soul apart. The wizard intent upon creating a Horcrux would use the damage to his advantage: he would encase the torn portion –”
_{^{- Harry Potter and the Half-Blood Prince, Chapter 23 (Horcruxes)}}

Since there’s nothing that states what fraction of the soul is split off to make a Horcrux, or what fraction is left, it’s not possible to deduce what fraction of his original soul the Dark Lord is left with.