Quick answer: A professional baseball game has 9 innings. Each inning has two halves, and each half ends after 3 outs. Each team puts 9 players on the field. The home team bats last. An MLB team plays 162 games a season, and the average game now takes about 2 hours and 38 minutes.
That is the whole game in four lines. The rest of this guide explains each part in plain words: how the innings work, how outs are counted, who bats first, what happens in extra innings, and how the rules change from the pros down to Little League.
The Goal of the Game
Baseball is simple at the top. Two teams take turns. One team bats and tries to score runs. The other team plays defense and tries to get outs. A run counts when a batter reaches first base, then moves around second base, third base and back to home plate. After the full game, the team with more runs wins.
Unlike most sports, baseball has no clock. A game ends when the innings are done, not when time runs out. That is why one game can last 2 hours and another can last 6.
Players on the Field
Each team has 9 players on defense at one time:
- Pitcher: throws the ball to the batter.
- Catcher: crouches behind home plate and catches the pitch.
- Infield: first baseman, second baseman, shortstop and third baseman.
- Outfield: left fielder, center fielder and right fielder.
The team at bat sends up one batter at a time. Since 2022, both MLB leagues use the designated hitter (DH). The DH bats in place of the pitcher, so the pitcher no longer hits in the pros.
A full pro team is bigger than 9 players, because it needs pitchers who rest, backup catchers and bench hitters. We cover roster sizes at every level in our guide to how many players are on a baseball team.
Innings and Outs
An inning is one turn at bat for both teams. It has two halves:
- Top of the inning: the visiting team bats. The home team plays defense.
- Bottom of the inning: the home team bats. The visiting team plays defense.
A half-inning ends when the defense gets 3 outs. Then the teams switch. There is no set time for an inning. A quick one can take 5 minutes. A messy one with many runs can take 30.
How many outs are in a baseball game? In 9 innings, each team bats for 27 outs, so there are 54 outs in total. If the home team is ahead after the top of the 9th, it does not bat again, so that game has fewer.
The main ways to get an out
- Strikeout: the batter gets 3 strikes.
- Fly out: a fielder catches a batted ball before it touches the ground.
- Ground out: a fielder gets the ball to first base before the runner gets there.
- Force out: a fielder with the ball touches the base the runner is forced to go to.
- Tag out: a fielder touches a runner with the ball while the runner is off the base.
This is why innings pitched are counted in thirds. One out is one third of an inning, so a pitcher who gets 1 out has pitched 0.1 innings, and a pitcher with 2 outs has pitched 0.2. If you have ever been confused by "5.1 innings", our guide on calculating ERA with partial innings explains it step by step.
Balls, strikes and walks
The batter is out after 3 strikes. After 4 balls, the batter walks to first base for free. A walk is a base on balls, shown as BB in the stats (see what a BB is in baseball). Being hit by a pitch (HBP) also sends the batter to first. Both are great for the offense, which is why on-base stats like OBP count them. You can see how they fit together with our OPS calculator.
Who Bats First and the Batting Order
The visiting team bats first, in the top of the 1st. The home team bats last, in the bottom half. Batting last is a small edge, because the home team always knows how many runs it needs. If the home team takes the lead in the bottom of the final inning, the game ends right there. This is called a walk-off.
Each team writes a batting order of 9 hitters before the game. The order does not change during the game, and it repeats. After the 9th batter, the 1st batter hits again. The common roles are:
- Leadoff (1st): gets on base the most, often with speed.
- 2nd: a good contact hitter who moves runners.
- 3rd: usually the best all-around hitter.
- Cleanup (4th): a power hitter who drives runners in.
- 5th to 9th: the rest of the lineup, with the weakest hitters last.
If a player is replaced during the game, the new player takes the same spot in the order. A player who is taken out cannot come back into the game.
Why the order matters: the top of the order gets more at-bats over a season. A team's best on-base hitters are usually placed first, so that hitters 3 and 4 have runners to drive in.
Extra Innings
If the score is tied after 9 innings, the teams play extra innings. They keep going, one inning at a time, until one team is ahead after a full inning (or the home team takes the lead in the bottom half). MLB regular-season games do not end in a tie. Spring training games can.
Since 2020, MLB puts an automatic runner on second base to start each extra half-inning. Fans call this the ghost runner. It was made permanent in 2023. The aim is to end long games sooner and protect pitchers' arms. We look at how it changes the stats in our article on the ghost runner and ERA in extra innings.
Rain and shortened games
A game does not need to go the full 9 innings to count. If rain stops a game, it is an official game once 5 innings are complete (or 4½ if the home team is ahead). A game stopped sooner is resumed or replayed.
How Long a Baseball Game Lasts
Because there is no clock, game time depends on pitching changes, walks, hits and breaks. It used to be getting longer every year. In 2022, the average nine-inning MLB game ran about 3 hours and 4 minutes. Then MLB added a pitch clock in 2023, and the average dropped to 2:40. It was 2:36 in 2024 and about 2:38 in 2025.
The pitch clock gives the pitcher a set number of seconds to throw: 15 with the bases empty and 18 with a runner on. The batter has to be ready in the box before time runs low. For more detail, including level-by-level times and the longest games ever played, read our full guide on how long a baseball game lasts.
How Long the Season Is
MLB has 30 teams. Each plays 162 regular-season games, 81 at home and 81 on the road. The 2026 season ran from late March to September 27. That is roughly 186 days for 162 games, with only a few off days. After the regular season, 12 teams go on to the playoffs. We explain the schedule, the history of the 162-game season and how other leagues compare in how many games are in an MLB season.
Because the season is so long, one game matters less than in football. Teams talk about "the long haul". Late in the year, though, every game counts. You can track a title chase with our magic number calculator.
Rules by Level: Pros, College, High School and Youth
The rules are close to the same everywhere, but game length and some details change. Use this table as a quick guide.
| Level | Innings | Players on defense | Notes |
|---|---|---|---|
| MLB | 9 | 9 | 162-game season, DH in both leagues |
| Minor leagues | 9 | 9 | Doubleheader games are 7 innings |
| College (NCAA) | 9 | 9 | Doubleheader games can be 7 innings |
| High school | 7 | 9 | Many states use a run (mercy) rule |
| Little League | 6 | 9 | Pitch counts protect young arms |
| Fastpitch softball | 7 | 9 | Pitchers throw underhand from 43 feet in most adult and high school play |
The number of innings also changes how stats are figured. A Little League ERA uses 6 innings, and a high school ERA uses 7, not 9. That is why you must never compare these numbers straight across. See our guides on a good Little League ERA, a good high school ERA and softball ERA vs baseball ERA. Check a young pitcher's workload with our pitch count calculator.
New MLB Rules That Confuse Fans
If you watched baseball 10 years ago, some things look different now. Here are the big changes:
- Pitch clock (2023): pitchers and hitters must be ready on time. Shorter games.
- Bigger bases (2023): 18 inches wide instead of 15. Easier to steal, and fewer collisions.
- Shift limits (2023): two infielders must stand on each side of second base. This helped batting averages on ground balls.
- Pickoff limits (2023): pitchers can only step off or throw over to a base a limited number of times per at-bat.
- Universal DH (2022): no more pitchers batting.
- Robot umpire challenges (2026): each team gets 2 challenges per game to question a ball or strike call. A team that wins a challenge keeps it. A team that loses two is done for that game. A pitcher, catcher or hitter can ask by tapping the helmet or cap right after the pitch.
Rules do change often, so check MLB.com for the latest official wording.
🎯 The Bottom Line
Nine innings, three outs per half-inning, nine fielders, and the visiting team bats first. A pro season is 162 games, and a game now lasts about 2 hours and 38 minutes.
Learn those few facts and you can follow almost any game. To decode the numbers in a box score, use our baseball stats glossary. The rest, like the batting order, extra innings and the pitch clock, builds on that base.
Want to go deeper into the stats?
Pitchers are judged by ERA. Hitters by average, slugging and OPS. Try our free tools to work them out in seconds.
Browse All Free Tools →Frequently Asked Questions
How many innings are in a baseball game?
A professional baseball game has 9 innings. College baseball also plays 9, high school plays 7 and Little League plays 6. If the score is tied after the last inning, extra innings are played until one team is ahead.
How many outs are in a baseball inning?
Each half-inning has 3 outs. When the defense gets the third out, the teams switch sides. A full inning has 6 outs in total, 3 for each team.
How many outs are in a baseball game?
A nine-inning game has 54 outs, because each team bats until it makes 27 outs. A game can have fewer if the home team is ahead after the top of the 9th and does not bat again.
How long is an inning in baseball?
There is no clock, so innings vary. An average MLB inning takes about 17 minutes, which is the average 2 hours 38 minutes game time divided by 9. A quick inning can take under 10 minutes, and a long one can take over 30.
Who bats first in baseball?
The visiting team bats first, in the top of each inning. The home team bats second, in the bottom of each inning. The home team bats last, so it can win the game with a walk-off.
Can a baseball game end in a tie?
Not in the MLB regular season or playoffs. If the game is tied after 9 innings, extra innings are played until one team leads. Spring training games can end in a tie, and some youth leagues allow ties because of time limits.