Nine, but if the game is tied it goes into extra innings.
5 innings
2
7 innings
7 innings unless there is a mercy rule
A regular baseball game has 9 innings. If the score is tied after 9 innings, extra innings are played until until the game is resolved. The longest running game in professional baseball history lasted 33 innings with 8 hours and 25 minutes of playing time. It was between the Pawtucket Red Sox and Rochester Red Wings from the Triple-A International League in 1981.
There are 9 regulation innings. It can go into extra innings if the score is tied.
Five innings constitute a game of rounders
5 innings
9 innings
2
If a game is tied at the end of regulation innings (9 innings in the MLB), the game will continue for as many innings as necessary until there is a winner. However, local leagues may set maximum innings or time limits.
There are 9 innings in college and MLB. There are 7 innings in high school. Either can go into extra innings in case of a tie.