Hello folks. Merry Christmas and happy holidays to all! 
Question; with the online ratings estimator here at the U.S.C.F. website, when estimating your updated rating after defeating an unrated player, what estimated rating value are we supposed to enter for the unrated player?
Thank you.
The ratings estimator doesn’t work very well with unrated players, because it doesn’t have the information needed to compute ratings for unrated players.
For detailed information on how ratings are computed, see this document:
glicko.net/ratings/rating.system.pdf
I haven’t tried it myself, but I’ve been told that putting in your rating + 300 points if you lose to an unrated and your rating minus 300 points if you beat him often produces a reasonable estimate of your new rating. (The actual process is a lot more complicated than that, as you can see if you read the above link.)
if you know the ratings of his opponents and score against them, you could first estimate his rating. be sure to change previous number of games to 0.