How Many Innings
in Baseball?

In a standard MLB game there are nine innings — but that number changes depending on where you are in the game, what level is being played, and whether the score is tied when the final out is recorded. Here's everything you need to know about how innings work across every level of baseball.

What is an inning in baseball?

An inning is divided into two halves — the top and the bottom. In the top half, the visiting team bats while the home team plays defense. In the bottom half, the roles flip. Each half-inning ends when the defense records three outs. Outs can happen via strikeouts, flyouts, groundouts, or any combination thereof.

How many innings in MLB?

A regulation MLB game is nine innings. If the home team is leading after the top of the ninth, the bottom half is not played — there's no reason to bat when you've already won. A regulation game is considered official once the visiting team has made 15 outs (five full innings) and the home team is leading, or once the home team has made 15 outs regardless of score.

Extra Innings — Regular Season

If the game is tied after nine innings, it continues into extra innings. Since 2020, MLB has used the automatic runner rule — also called the "ghost runner" — where each extra half-inning begins with a runner on second base (the player who made the last out). This rule was made permanent in 2023 and applies to all regular-season games. It dramatically speeds up extra-inning resolution — in 2024, just seven of 216 extra-inning games went past 13 innings.

Extra Innings — Postseason

The ghost runner rule does not apply in the playoffs. Postseason extra innings revert to traditional rules — bases empty, play baseball. The 2025 World Series featured an 18-inning Game 3 between the Toronto Blue Jays and Los Angeles Dodgers at Dodger Stadium, the longest World Series game since 2018.

The Pitch Clock

Introduced in 2023, the pitch clock has cut the average MLB game from over three hours to approximately 2 hours 36 minutes. Pitchers have 15 seconds to deliver with bases empty and 18 seconds with runners on. Batters must be ready with eight seconds on the clock. Violations result in automatic balls or strikes.

How many innings in high school baseball?

High school baseball games are typically seven innings. The shorter format reflects several practical realities — limited daylight since games often start between 4 and 5pm, the need to balance schoolwork and athletics, smaller rosters with fewer available pitchers, and pitch count limits designed to protect young arms. Some states may have variations, but seven innings is the standard across the country.

How many innings in college baseball?

College baseball follows the nine-inning format used in the pros. However, the NCAA allows seven-inning games for the final day of a conference series or during non-conference doubleheaders — both games of a doubleheader are typically seven innings each. Mercy rules also apply in college baseball: if one team leads by a set run margin after a specified number of innings, the game can be called early.

How many innings in youth baseball?

Youth baseball innings vary by age group and organization. The general pattern is fewer innings for younger players — a reflection of shorter attention spans, developing physical stamina, and pitch count protections designed to protect young arms.

How many innings in minor league baseball?

Single-A, Double-A, and Triple-A minor league games all follow the nine-inning format. Minor league games tend to run faster than MLB games due to the 20-second pitch clock implemented at the AAA and AA levels, which reduces average game time by roughly 12 minutes. Doubleheaders in the minor leagues consist of two seven-inning games rather than two nine-inning games.

What happens if the home team is winning in the 9th?

If the home team leads heading into the bottom of the ninth and has already recorded three outs in the top of the inning, the game is over. The home team doesn't bat — there's no way for the visiting team to score again, so there's no need to play the bottom half. This is why you'll sometimes see an official game score that shows only 8½ innings played rather than a full nine.

Historical marathon games

Evolution of baseball innings

Baseball didn't always have nine innings. In the 19th century, early baseball had no standardized inning count — rules varied by region and by agreement between competing teams. As the sport professionalized, consistency became necessary. The National League, formed in 1876, established nine innings as the standard to create a predictable, balanced game structure. That standard has held ever since, though surrounding rules — from extra innings to the pitch clock — continue to evolve.

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