I've been told the maximum number of players at a Texas Hold'em table is 10. Why?
The ideal max number at a regular-size table is 9 players and a dealer. 10 is also not uncommon. Some larger tournaments will occasionally place 11 at a table in the early stages until the field is narrowed a little. Any more than that and you'll have a game that is super tight, both in terms of the poker and the space available to you. The theoretical max at a table is limited only by the number of cards available in the deck. 52 cards, and 8 are used up as part of the board (5 cards shown plus 3 total burn cards). That leaves 44 cards remaining, and each player gets 2 of them, so I guess you could have 22 players if you had a big table and skinny people. Of course, a game like this would be no fun for anyone, dealer or players.
In the 80s I played in clubs that routinely spread 13-14 hands on a big table (often a "violin" table more commonly used for Baccarat). That's very unusual nowadays, since casinos know that slows down the rake, so most spread only 9 or 10 now.
Theoretically, without burns, you could have 23 players. Early Internet games on IRC would spread a tournament this way, and it was a quite playable game.
10 Is max, more players would just kill the game... If you play poker for a longer time I think you would agree with me. I prefer to play 6max on cash game, it's faster and more skilled.
Think if 20 people sat on one table. They would rarely pay blinds and everyone would be waiting to hit some strong hand and nobody would play which kill the thinking game of poker.
If you try to play heads up tons of play is around bluffing and exploiting your opponents weaknesses which is very fun.