Baseball Field Dimensions

posted on December 30th 2007 by Troy Frazier

Baseball and Softball Field Dimensions

There are a number of sites with dimensions for baseball and softball fields. I would like to consolidate some of that information and clear up a few points of confusion. I’ve also included youth baseball dimensions which can be difficult to find.

The back of home plate is the starting point for our measurements. The back of the home plate points to the catcher and the backstop. Home plates are surrounded by a black rubber. Don’t include the black rubber in your measurements, measure from the white part of the plate to the back corner of first base. This is the corner of the base closest to the foul line and furthest from second base. The next measurement goes from the back corner of first base to the CENTER of second base. Now measure from this point to the back corner of third base, and then back to our original point on home plate. This square will have equal sides, and 90 degree angles. The line from the back of home plate to the center of second base can be calculated with the Pythagorean Theorem A^2+B^2=C^2. See table 1.

Table 1

Standard bases are 15 inches by 15 inches. If you are trying to find a base peg (anchor), subtract 6 to 7 inches from the baseline number above. For example: the base anchor for first base on a high school field will be roughly 89 feet 6 inches from the back of home plate. A metal detector can be very helpful for finding base pegs since they are frequently installed incorrectly.

The pitching area is not in the center of the square formed by the bases. Do not use the front of the rubber as a reference point between first and third base. The skinned infield (dirt part of the field) is measured as a radius from the front of the pitching rubber.

Table 2

Subtle changes in base paths and pitching rubber distances make it difficult to calculate the exact area of the skinned infield, but the numbers expressed in table 3 are generally close. Table 3 also shows the approximately how much baseball dirt (infield mix) is needed to get one inch of coverage for different fields. This number can vary depending on the type of infield mix used. It’s best to order full truck loads of bulk material. A legal full truck is 20 tons (roughly 16 yards).

Table 3

Softball rules are very clear about base paths, and backstop distances. The skinned infield must extend at least 3 feet past the foul line before grass starts and backstops must be a minimum of 25 feet from the back of home plate. Softball umpires will enforce these rules. Baseball is more lenient on these measurements. Base paths are generally suppose to be 6 feet wide (grass infield only), but many coaches prefer a narrower base path because narrow base paths dry faster after a rain. Table 4 shows some recommended back stop positions, and diameters for home plate circles.

Table 4

On deck circles normally have a 5 foot diameter. Base cutouts are measured from the back corner of the base (closest to the foul line, furthest from home). Table 5 shows cut out radiuses and recommended distances for dugouts from the foul line.

Table 5

The outfield fence is measured from the back of home plate, but the arc of the fence is not necessarily set from any point on the field. This is why the outfield fence dimensions are hard to establish. Table 6 shows the distance from the back of home plate to center and left field.

Table 6 Home Run Fence Dimension

Softball uses a 16 foot diameter circle for the pitching area. Baseball uses a pitching mound. A major league mound is 18 feet in diameter and 10 inches higher than home plate. The pitching rubber is installed 18 inches back from the center of this mound. A lot of people don’t realize that the mound is flat on top. The flat area is 5 feet by 34 inches. 6 inches in front of the pitching rubber is flat, and then begins to grade down one inch per foot. Table 7 shows mound diameters and heights.

Table 7 Pitching Mound Dimensions

It is very common for mounds to be built much higher than this. The grade of the field can make the mound area several inches higher than home plate before you start building the actual mound. Umpires rarely enforce rules about pitching mound height unless it is clearly too high.

This is the first draft of this document. Please let me know if I’ve made any mistakes.