I know there is no relation between chess.com rating and actual rating...

But how can someone get the judge of his rating before playing any rated open tournaments... In chess.com my rating hover around 1700-1800, but last week I played an rated player of 1580 and he beat me easily. Here there should be a way there the rating gets adjusted as much as possible.

Probably there should be some engines running various playing strength, and we can play against them to get our ratings adjusted...

Just 2 cents of suggestion for chess.com, in case they are reading it.... :)

ll is there some computer program u can play to make ur actual rating higher without playing a person? so why should there be one here?

There is no correlation. I have seen people rated 2000 who are rated 1400 in real life. They can achieve this by choosing people who they play against, whereas in real life (tournament chess) you don't get that choice.

my online rating currently hovers around 1900, in the past on other chess sites it has been as high as 2100...

in tourney's i have beaten 1900s. 

i think that there may be a correlation, however i believe it is about your mindset for the game, if you approach an OTB rated game as if it were online you will have a harder time.

just my 2.35667 cents