What is the Strike Zone in Baseball?

Last updated on November 3rd, 2023 at 08:39 am

There is no visible strike zone that a pitcher, catcher, hitter, or umpire can see when someone is at the batter’s box. However, the strike zone box that you see on TV helps fans visualize a strike and a ball from a pitcher. MLB also uses this box to calculate the effectiveness of an umpire calling balls and strikes during a game.

Instead of an actual box for strike calls, the general strike zone forms to the height of a hitter’s swing and measures from the batter’s shoulders to the batter’s knees. From left to right of the strike zone represents the width of the home plate, which is 17 inches. However, the strike zone is ultimately up to the umpire’s discretion, making balls and strike calls interesting.

If you want the official rulebook and definition of the strike zone, you can visit this link. Essentially, the strike zone is the midpoint of the batter’s armpits at the top, the middle portion is the top of the uniform pants, and the bottom of the location is the kneecap area.

Table of Contents

A Video Explaining the Strike Zone

What’s the Point of the Strike Zone?

The strike zone is valuable to the pitcher and the hitter during a baseball game. The pitcher needs to record outs against a hitter, so it’s a combination of getting hitters to get out via contact, a called strike, or swinging and missing at the ball. For the hitter, the strike zone will have the most success making hard contact with the ball, so they tend only to swing when it is a strike.

If there were no strike zone, like in the 1800s, you would have pitchers throwing all over the plate and not remotely close to the hitter. For the hitter, the strike zone represents a limited number of pitches they see. For example, a hitter can’t let six straight pitches go down the middle of the plate if they are looking for something different. After the third called strike, the hitter is out, which helps speed up the game since there are 27 outs during a baseball game.

Why Do Some Umpires Have Different Strike Zones?

Home plate umpires determine balls and strikes, and every umpire has a slightly different strike zone from each other. Some umpires tend to favor the bottom of the strike zone more than the top. Others tend to give the pitcher more to the left and right of home plate for strike calls. Some umpires are more hitter-friendly, and so on.

While MLB tracks every pitch and scores the effectiveness of an umpire’s ball and strike calls, baseball players tend to want a consistent strike zone during a game, regardless if it is 100% accurate. Major League baseball players tend to argue balls and strikes when the home plate umpire becomes inconsistent with calls throughout the game. Players arguing balls and strikes tend to lead to an ejection, but sometimes umpires realize they made the wrong call and allow them to complain a bit.

Why is the Size of the Strike Zone Not a Universal Height?

While the strike zone is typically 17 inches wide, give or take, the height of the strike zone depends on the hitter’s size and swing. For example, Aaron Judge stands at 6 feet and 7 inches, making his strike zone different from Dustin Pedroia standing at 5 feet and 9 inches. Since the strike zone tries to make a box via the batter’s stance, you will see two different boxes during a baseball game if you see a side-by-side of Judge and Pedroia batting.

How Does the Strike Zone Effect the Game?

One missed call for your team can become a massive momentum shift. For example, let’s say your pitcher throws a pitch that appears to fall in the strike zone, but the umpire does not call it a strike. That pitch would have been strike three during an at-bat, but it was questionable to the umpire since it was at the bottom of the hitter’s knees. On the very next pitch, that hitter hits a home run, and now players feel robbed of that “should have been called” third strike.

On the flip side, a pitcher can get an incredibly generous called third strike against a hitter. You’ve seen it all the time where the ball appears low or high against the invisible strike zone, but the umpire calls it a strike. That might be the third strike to a hitter, which means they are out on a questionable call.

Finally, consistency is something that every hitter and pitcher is looking for during a game. For example, a starting pitcher may notice that the umpire calls strikes at a specific spot. While that might not be a strike according to the K zone, the pitcher and batter understand that that pitch will be a strike during the game.

How Much of the Ball Needs to be in the Strike Zone?

Generally speaking, the pitched ball needs to go through the imaginary strike zone to be a strike. The pitch can also clip the corner of the box, so it doesn’t need to be 100% inside the strike zone box. However, there are times where an umpire may miss the call, especially if the pitch is towards the top corner part of the strike zone of a hitter.

Will the Strike Zone Turn to Robot Umpires?

With instant replay and high definition in baseball, it’s only a matter of time for robot umpires to start calling balls and strikes. While fans want the human part of the game, others are open to that idea of a bot calling strikes and balls. MLB is testing an Automatic Ball-Strike System in Low-A baseball in 2021 as the pilot. Whether or not this comes to the MLB is uncertain, but baseball tests all new rules and systems in the minors to perfect the design before arriving in the MLB.

Conclusion on the MLB Strike Zone

The Major League Baseball strike zone is one of those unique things that separates it from other sports. Just like how hitters have slightly different batting stances to bat from each other, so is the strike zone at times. While the general rule of the thumb for a strike is the width of home plate and between the shoulders and the kneecap of a hitter, some umpires might have a slightly different strike zone during a game.