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

Solution 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.