I would say when you reach 1000, or 1200 rating on this website you are no longer a beginner.
how can we tell when someone stops being a beginner?
Roughly speaking, an intermediate rating tends to start somewhere between 1200/1400 and ends around 2000.
This might seem like quite a 'high' rating to be classed as an intermediate. I believe it more so comes from the fact that most learning materials aimed at 'intermediates' are best suited for players from this rating range and higher, as players U1200 would still benefit more from tactical exercises and getting a handle on undefended pieces.
There's no point learning hours of strategical middlegame concepts aimed at giving you a slight improvement, if you drop a piece (or even a pawn) just through lack of board vision.
Somewhere around 1200-1400 is when most players start to phase this out of their games enough that one-move preventable material losses are not a reoccurring theme in their games.
Outside the 'chess world' though, I'd say a 1000 is where the intermediate starts. A 1000 definitely has enough comprehension of the game to the extent that they could play continuously against casual opposition and win at least half of their games.
I think chess.com places 850 at the 50% mark in terms of playing strength against the mass public.
I couldn't have said this better myself. Undefended pieces are always a tactical theme though, you should always watch out for them as they are a magnet for tactics.

I always thought that isn't really a compliment, if we accept that self-praise is no praise at all.
ROFL - that's hilarious. Super reversal given it's supposed to be one of the highest complements.

When you don't have the foundation or proper coaching, your strength could be all over. 1100 in opening 1300 in tactics 800 in strategy and 500 in ideas. And this even apply to higher ratings. So sometimes you win against high rated players because you saw a tactic or they are even worst in their opening knowledge etc. The day that you almost never lose to certain ratings is your true rating.
When you don't have the foundation or proper coaching, your strength could be all over. 1100 in opening 1300 in tactics 800 in strategy and 500 in ideas. And this even apply to higher ratings. So sometimes you win against high rated players because you saw a tactic or they are even worst in their opening knowledge etc. The day that you almost never lose to certain ratings is your true rating.
No, your true rating is your rating. Your rating is a representation of all of your games.

I would consider someone a beginner until they master all the basic tactical motifs, attempt to follow solid opening principles, and know basic endgame techniques such as king+ rook mate, drawing a king v pawn vs king ect... From what I've seen 1300 is probably around the rating when all this stuff comes together, and you can call yourself an "intermediate" instead of a beginner

I would consider someone a beginner until they master all the basic tactical motifs, attempt to follow solid opening principles, and know basic endgame techniques such as king+ rook mate, drawing a king v pawn vs king ect... From what I've seen 1300 is probably around the rating when all this stuff comes together, and you can call yourself an "intermediate" instead of a beginner
When I was 1500 I wouldn't even have felt comfortable saying I had mastered "all basic tactical motifs" - I didnt even know what Hook Mate or Greco's Mate was until I was 1600!
1200?