It's impossible to know exactly because online chess is different (short time controls, cheating, etc).
But, as unpopular as it is to estimate, I'll say my estimate for you is 1000.
Blitz is usually a little low at those levels, and standard is usually high.
The only way to be sure though is to play in tournaments.
my rating here is 1320, does it means that my official rating will be almost same?
almost!
you think my rating is 1000?
Chess.com standard rating is usually much higher than Elo.
Chess.com blitz is usually a little lower.
So my guess is somewhere in between. I think 1000, but this is just a guess. In some sense it's a meaningless guess. But I think it would be frustrating for you if 20 people answered your topic and no one gave you a number, so I gave you my guess.
To know for yourself you would have to play in tournaments. If you want a better estimate, find a chess club and play some casual games with tournament players in your area. By playing and talking about the game they will get a good sense for your ability and tell you how you compare.
If there was chess.com rating correlated to your OTB rating, it would certainly be your standard rating. Generally, the standard rating is a bit higher, but it decreases as you approach a point between 2000 and 2100. So maybe your "virtual" OTB rating could be estimated with a formula like :
OTB = standard - standard*[(2100 - standard)/k]
with k a constant we could fix at 3000, and standard < 2100 of course.
I don't know if that's worth something, though...
I found this to be an interesting comparison:
http://www.chess.com/forum/view/general/fide-ratings-vs-chesscom-ratings-explored
"Interesting" - anyway... Not sure about "valid"... but conclusions from this ad hoc statistical exercise are that chess.com ratings are a little deflated compared to OTB ratings. I guess the reason I find it interesting is that it suggests that there might be some hope for me one day in not being laughed out the door if I tried to join a local chess club! 
There are a few good forum topics that attempt to compare ratings. Some have tried to gather a lot of data.
Remember though, when looking at these old topics, that since then chess.com has artificially injected hundreds of points per player into the standard ratings.
aha ok, but i think 1000 is too low, but i will increase.
thanks.
Yes, maybe it is higher. But I'm sure you will improve quickly so it doesn't really matter :)
I found this to be an interesting comparison:
http://www.chess.com/forum/view/general/fide-ratings-vs-chesscom-ratings-explored
"Interesting" - anyway... Not sure about "valid"... but conclusions from this ad hoc statistical exercise are that chess.com ratings are a little deflated compared to OTB ratings. I guess the reason I find it interesting is that it suggests that there might be some hope for me one day in not being laughed out the door if I tried to join a local chess club!
with this formula my fide rating will be from 1330 to 1724 and it's nice but is it trusty formula?
with this formula my fide rating will be from 1330 to 1724 and it's nice but is it trusty formula?
The estimation is based on former standard ratings, which were 150 to 500 points lower than now (there's been an artificial inflation a few months ago). So... not so trusty, unfortunately.
But you know, as leiph18 correctly emphasised, the only way to know is to play OTB games.
Don't you mean + 300 for blitz?
I don't pretend to be a great or even a good player, but I disagree about the significance of blitz-playing ability in relation to OTB ability. Maybe it just depends on your particular strengths and weaknesses though. I can play a relatively good game - but I need time to think and in blitz, when I try to calculate or analyze the position, or do anyhting other than play by intuition alone, I loose on time. But I have been noticing that many of the people who I play good games agianst using standard time, or on-line have much, much higher blitz ratings than I do...
I found a link with a graph, which might be more straightforward.
http://www.chess.com/article/view/chesscom-rating-comparisons
That would make me an 800 player otb :-/
ok i'll be more generous
live blitz - 299 = otb rating
Eesh I think blitz is 100 to 150ish lower. And standard is probably 100-200 higher.
http://www.chess.com/livechess/game?id=1065975285
yeah i guess they hand out Nm at 1600 now according to "MyUSFCis1729"/A_L_I_V_E/ other accs
live blitz - 300 = otb rating
It depends on what your chess strength is in. You are probably one of those people who don't benefit from classic time controls. My classic OTB rating was consistently 400 points higher than my online blitz ratings. Some people do benefit from having more time to think...
hey guys i can't understand which is right leiph18 said thath my raiting is 1000 but when i saw this link my rating is 1450.
Remember post #9.
Standard ratings have been inflated since that article was written. One day chess.com added between 100 to 500 points to every active player's standard rating.
Also, I suppose I was thinking USCF. I see from that link ~1000 USCF = ~1200 FIDE. Maybe this is because there were only 250 people who offered their ratings as data. Maybe this is because historically FIDE ratings weren't below 2200.
If i want to know what is my rating but i am only playing on this website, how i can to know?