Field Dimensions Guide

Laying Out Your Ballfield

1. What is the sun’s angle at your ballfield?

How will the sun impact the ballplayers at the time of day when most games will take place on the field? This is a very important consideration because it can affect every player on the diamond — batters and fielders alike.

Ideally, you should aim to keep the sun out of the batter’s line of sight. It is very difficult, and even dangerous, for a batter to try to pick up a pitch when looking either directly or indirectly into the sun. In other words, it is best to keep the sun entirely behind the batter’s head so it does not present a problem during play.

It is also very important to make sure the sun angle will impact as few of the fielders as possible. Generally speaking, the best angle for both batters and fielders is to have the centerline of the field run from southwest to northeast with home plate at the southwestern end. The centerline of the field is the imaginary line running from the apex (back point) of home plate, through the middle of 2nd base, and on to centerfield.

2. Where do you want home plate to be?

Now that you have an idea of which direction the field should face, choose where you want home plate to be located. Check with your ruling jurisdiction for the proper distance between home plate and the backstop (see Field Dimensions Diagrams in the RED section). If there is already a backstop installed at the field, make sure that you center home plate with the backstop. The objective is to have the centerline of the field be a continuation of the centerline that runs from the existing backstop to home plate. Place a pin, stake, or marking flag where you want the point of home plate to be located.

3. Stake out 2nd Base.

Next, using a 200-foot (or longer) measuring tape with one end attached to the stake at home plate, measure out in the direction that you want to place 2nd base. Drive another stake at the proper distance for 2nd base, according to the ruling league or jurisdiction that you are in (see Field Dimensions Diagrams in the RED section). This point should be the exact center of 2nd base and should fall on the centerline of the field.

4. Now, stake out 1st & 3rd.

To find the location for 1st base, extend the measuring tape from 2nd base in the direction where the approximate location for 1st base will be. Be sure to measure the required distance according to your league. Then, extend a second measuring tape from your home plate stake toward 1st base. The point at which these two tapes intersect with equal distances from home plate to 1st and 1st base to 2nd is where you will place another stake. This point will be the back outside corner of 1st base. Repeat this process to find the location of 3rd base.

5. Locate the pitching mound.

After locating home plate and the three bases, you need to locate the pitching mound. The center of the mound is again located on the centerline of the field at a set distance from home plate that is dictated by rules of the league that will be using the field. This distance is always measured from the apex of the white portion of home plate toward 2nd base. The black outside edging on the plate is not considered part of home plate and, therefore, is not included when measuring.

6. Finally, the foul lines and foul poles.

To locate where the foul poles and the outfield foul lines should be located, it is best to use the geometric formula for a right triangle, A² + B² = C². To find the left field foul line, let A equal the distance between 2nd and 3rd base. Let B equal the distance you want the foul line to extend past 3rd base to the foul pole. Square each of these two numbers. Add them together. Then take the square root of the sum of the two numbers to calculate the length of C, or the hypotenuse. Follow the sample below. Once you have values for A, B and C, you can go to work in the field triangulating the location of your foul pole.

Place the stake at the back corner of 3rd base. Place another stake in the exact center of 2nd base (if you have been following the steps above these stakes should already be set). Extend a 300-foot measuring tape from each of these stakes towards the left field foul. The tape that is running from the 3rd base stake should be extended out to the distance B in the above calculation. The other tape should be extended out from 2nd base to the distance C. This distance, the hypotenuse, is the longest side of the right triangle that you formed between 2nd base, 3rd base, and the left field foul pole.

Pull the two measuring tapes toward each other until they intersect at the appropriate distances, B and C. Place a stake or marker of some type at the location to mark the left field corner, as shown below in Figure 2. Repeat this process using 1st base, 2nd base, and the right field corner to locate the right field pole.

Foul Pole Calculations

For all right triangles, the following formula holds true:

A² + B² = C² [Diagram of a right triangle demonstrating formula]

Let A = 90 ft. This is the distance between 2nd & 3rd base.

Let B = 240 ft. Let’s suppose this is the distance you want the foul line to extend from 3rd base to the left field foul pole. This would make the left field foul line 330 ft long on a baseball field with 90 ft baselines.

Now, let’s apply this to a ballfield. Using the right angle formula and the values above, we see that:

[Foul pole calculation diagram]A² = 90 × 90 = 8,100 ft
B² = 240 × 240 = 57,600 ft

and, since A² + B² = C² then:
C² = 65,700 ft

To find the value of C, we calculate the square root of 65,700.

Therefore, C = 256.3 ft.

To convert that decimal into inches, you multiply the number of inches in a foot by 0.3.

12 in/ft × 0.3 ft = 3.6 in

From these calculations, we know the distance from 2ND BASE to the LEFT FIELD FOUL POLE (C) is:
256 feet 3.6 inches

Alignment of the Foul Line to the Foul Pole

[Diagram of alignment between the foul line and foul pole]The foul edge of the foul line should always align with the foul edge of the foul pole.