rules for castling

hello - what are the rule for when Chess.com will and will not allow a player to castle?  had some family perplexing experiences on here where I could not castle to either side despite not having moved King or Rook previously...

Rules are the same as the official rules of chess.

https://support.chess.com/article/266-how-do-i-castle

In addition to what you posted you can't castle when your king is in check, can't castle into check, and the king can't move through a square attacked by your opponent's pieces, i.e. castling through check.

I had an interesting one i was playing against the computer and it castled queen side and the rook passed through check, after a bit of reading it is okay to do that. The comments above are totally correct.

There's no such thing as "check to a Rook". That's why it's not a problem.

Point taken.

lmao

In real-life games there are also conventions related to castling, many of which are actually tournament rules (if you are playing in a tournament). For example, no castling with two hands (taking the king with one and, at the same time, the rook with another, and move them simultaneously). And when you castle with just one hand, moving one piece at a time, you move the king first, never the rook first (technically if you touch the rook, you have to move it, and you can't castle with it).

In casual games these conventions may often be overlooked, but it's still "polite" to follow them.

(Also, if playing with a clock, you press the clock with the same hand you moved the piece(s). Deters cheating with the clock.)