Convert my performance into FIDE rating

You can play on FICS and use the command conver elo. I played 1 game and got from 1200 to 1300, used the function and it told me the same number as my rating lol on FICS lol.

I would be probably be 700, 800 in OTB rating. I lose against a personality rated 1208 in the chessmaster 9000 edition. This lichess rating is extremely overrated.

"I would be probably be 700, 800 in OTB rating. I lose against a personality rated 1208 in the chessmaster 9000 edition. This lichess rating is extremely overrated."

Chessmaster has its own weird system. Personalities and training are different too. Again you cant really compare.

For example FIDE, USCF and CFC also have a bit difference.

Of course, OTB matches are usually longer time controls than most games here.

And different player pools/ratings systems.

@#10 average rating gives x shift of the rating distributions. If you assume the player pool strength are the same (and there's no reason not to) then it should be pretty straightforward and accurate.

I have 1850 FIDE and 1955 lichess ("classical"). I play irregularly in tournaments and county chess for about 20 years.

It is very diferent to play over the board or online. You would need to adapt. The classical FIDE rating is obtained in games that can last up to 6 hours each (typical is 2 to 3 hours). Most people here just woldn't use the time and end up playing well bellow their potential. But if you can hold on with strong players online you can do the same over the board. Just don't expect it to be automatic.