How does recalibration and rank promotion work in Dota 2 Season 4?

Question

I was about 4,900 mmr in Season 3 in my support MMR but I believe I lost at least 7 games out of 10 and only ended up in 4,700 mmr for Season 4. I was told that you lose -75 for every loss and gain +75 for every win in recalibration, but this doesn't seem to be true. However, I calibrated in Ancient 5 from Divine 4.

Then I decided to play my core recalibrations and ended up winning 9 games out of the 10. Then I jumped from Ancient 5 to Divine 2 (With 15% to the next rank). I was initially around 4,700 or 4,800 but i'm now 5,250 MMR. However, I was only around 5k when I hit Divine 4 last season, i'm wondering why I am only Divine 2 this season--but I would guess it has definitely something to do with the distribution of players and their MMRs. Also I noticed that every win will give me around 20% increase on my progress to the next rank.

So my estimate is that:

Divine III - around 5,350

Divine IV - around 5,450

Divine V - around 5,550

Divine VI - around 5,650

Divine VII - around 5,750

Immortal - 5,850 and above

I have been looking at some data online, but the numbers do not seem accurate to determine what MMR you need to reach each rank, but since the progress % is always about 20% per win, then it should make sense that the MMR required to reach a certain rank should be readily easy to calculate. But since I have only me as a data point, I cannot say if this is true for all.

Answer 1

Recalibration

It is not possible to know exactly how many mmr you got from each calibration/recalibration match as that value is hidden. However, many people have speculated it to be between 50-75. If you've lost 7 out of 10 calibration games i.e. 4 net losses, and lost 200 mmr, that would leave you with -50 per loss in your recalibration, which would still fall into the anecdotal range.

Ranks

Ranks are based on player percentages, not a specific mmr. As such, towards the end of a season, it is generally easier to achieve a higher rank even if you did not play any game recently, due to the inflation in mmr. That's the reason why you will never find an accurate estimate unless it is updated at least weekly.

For example, in Season 3, I calibrated at Ancient 3 during the start of the season. Towards the end of the season, I played and lost exactly one game but I got promoted to Ancient 6. This is because the average level of the players at Ancient 3 have dropped and my mmr is closer to that of an Ancient 6 at the end of the season, compared to that at the start.

Also, there was a change to stars per rank around October. Now that there are only 5 stars per rank, players have been pushed up accordingly. I recalibrated at Ancient 5 at the start of Season 4, but after that rank update I was moved to Divine 1 despite not having played any game.