Quick answer: A high school, college or pro mound is an 18-foot circle whose center is 18 inches in front of the rubber. The top of the 24 x 6 inch rubber is 10 inches above home plate, and its front edge is 60’6″ from the back point of home plate. A 5′ x 34″ level top surrounds the rubber; the slope starts 6 inches in front of it and drops 1 inch per foot for 6 feet. A standard Little League mound (Majors and below) is a 10-foot circle at 46 feet, 6 inches high. Build it in thin, moist, tamped lifts: high-clay packing clay on the table and landing area, infield mix on the back and sides. Keep it tarped.
Pitching mound dimensions by level
| Level | Pitching distance (front of rubber to back point of home plate) | Mound circle diameter | Height above home plate | Pitching plate size | Source |
|---|---|---|---|---|---|
| Little League Major/Minor | 46 ft | 10 ft | 6 in | 18 x 4 in | LL field layout; 50/70 conversion guide |
| Little League Intermediate (50/70) | 50 ft | 12 ft | 8 in | 18 x 4 in | Intermediate mound layout; conversion guide |
| Junior/Senior League | 60’6″ (Junior League option: 54 ft) | 18 ft | check rulebook | check rulebook | Jr/Sr field layout; field specifications |
| High school / college / pro | 60’6″ | 18 ft | 10 in | 24 x 6 in | MLB rules; HS: check your state association |
Murray Cook, writing on MLB’s groundskeeper blog, says 10 inches is mandatory in major and minor league and NCAA baseball and is used by most high school programs; confirm with your state association or the governing body for your level of play.
The geometry most people get wrong
- The rubber isn’t in the center. The circle is centered 18 inches in front of it: 59 feet from home plate on a 60’6″ field (Cook), 48’6″ on an Intermediate field (Little League).
- The level top is 5′ x 34″. Beam Clay runs it 18″ either side of the rubber, 22″ behind and 6″ in front: 18 + 24 + 18 = 60″ wide; 22 + 6 + 6 = 34″ deep.
- It isn’t a cone. Beam describes a large flat top, steeper back and sides, and a gradual 6-foot front slope.
- Height is measured from home plate. NC State Extension calls miscalculated mound height “probably the second most common error in setting up a baseball field.” Cook: “not 10 inches above the grass.”
Tools and materials
Combined from Profile Products (Turface), Cook and NC State:
- Plate compactor and a heavy hand tamp
- Pick, square-faced shovel, landscape and steel rakes, wheelbarrows and helpers
- 100-foot tape, steel spikes, string and line level, or a transit/laser
- Ten-foot 2×4, four-foot 1×4, carpenter’s level and a mound slope board
- Small tiller, hose and water
- A four-sided rubber; Cook likes a block type you flip yearly for four years of use
- Hard packing clay for the table and landing area (Cook: about 40% sand, 40–50% clay, 10–20% silt) and infield mix for the rest (about 60% sand, 30% clay, 10% silt)
How much clay to build a pitching mound
These figures don’t agree because they measure different things: whole mound vs. wear areas, bagged clay vs. total soil. Order to the source that matches your method.
| Source | Figure | Covers |
|---|---|---|
| Murray Cook | 8–10 tons: 2 tons hard clay + 6–8 tons infield mix | New or fully rebuilt mound |
| Beam Clay | 5 tons (200 bags) | Whole mound from scratch |
| Beam Clay | 2 tons (80 bags) or less | Finish over a firm base, at least 6″ in all wear areas |
| Beam Clay | About 1/3 as much: 13 bags per 1″ of depth | Little League mound |
| Turface 5-Star listing | Approx. 7 tons | Full baseball mound construction |
| NC State Extension | 3–4 cubic yards of soil or infield mix | Building and maintaining |
| Beacon ProBrick guide | 6″ mound: 106 bricks; 8″: 158 or 252; 10″: 243 or 389 (2.5″ or 4″ deep) | Table and front slope only |
What it costs
Listed online October 2026, before shipping: Turface 5-Star Packing Clay, $26.11 per 50 lb bag at Advanced Turf Solutions; DuraEdge ProLoc Mound Blocks, $38.14 per bag of 8 at Reinders. As an illustration only, using Beam’s bag counts: 80 bags x $26.11 = $2,088.80; 200 bags x $26.11 = $5,222.00. Freight on heavy clay can be significant, so get delivered quotes; see where to buy infield dirt and mound clay.
Step-by-step: building a regulation mound
- Set the line and spike. Run a string from the apex of home plate to the second-base peg, measure 60’6″ and sink a spike marking the front and top of the rubber (Profile, Beam).
- Mark the circle. Cook pins the 59-foot point, 18″ in front of the rubber, and swings a 9-foot line around it. Protect existing grass with geotextile and plywood.
- Prep the base. Loosen existing soil with a pick so new clay bonds (Profile). Beam’s bonding layer: mix at least 1/2″ of dry mound clay into the top 1″ of existing material, then wet and compact. On a sandy mound, Beam first removes 6″.
- Build in thin, moist lifts. Cook, NC State, Profile and the Brewers’ Michael Boettcher use 1-inch lifts; Beam and the Twins’ Larry DiVito cap them at 2 inches. Cook wants the clay “just a bit drier than that of Play-Doh”; Beam’s test: a thumbnail just barely pushes 1/4″ into the compacted clay. Tamp and rake-scratch each lift (NC State), skip conditioner between layers, and check height every lift against a pin set 10 inches above home plate (Cook).
- Hard clay in wear areas. Cook: at least 6–8 inches on the plateau and landing area. Beam: the top 6″ of all wear areas in straight mound clay. DiVito: a solid 4 inches if maintained and tarped, about 6 at the pro level.
- Set the rubber. At 10 inches, Cook builds the 5′ x 34″ plateau and sets the rubber level both ways, centered on the home-to-second string. Square it: home plate front-corner to rubber front-corner measurements must match left and right. A solid concrete block underneath keeps it from shifting (Profile).
- Cut the front slope. It starts 6 inches in front of the rubber and falls 1 inch per foot (Cook). Profile lays a four-foot 1×4 on the rubber to the plateau edge and a ten-foot 2×4 on its side from there to the turf; two people saw it across the landing area as clay goes in, then tamp hard. Check it with a Beacon slope gauge, leveled against the rubber, reading marks 1 through 6.
- Shape the back and sides. Cook uses infield mix from the plateau’s back edge, guided by a plank to the grass. Beam keeps them steeper than the front. Finish with one continuous circle (Cook).
- Finish and tarp. Cook adds a 1/8-inch layer of conditioner (see calcined clay vs infield mix) so it won’t stick to the tamp; Profile spreads one or two bags, moistens, rolls and tarps.
Little League and youth mounds
A standard Little League mound is a 10-foot circle with an 18 x 4 inch plate at 46 feet, 6 inches above home plate. Little League’s 50/70 conversion guide adds a second plate at 50 feet, 8 inches high, on a 12-foot circle centered 48’6″ from the back point of home plate, and says contouring isn’t necessary if the infield is crowned (see how to grade a baseball field). Little League’s documents give no plateau or slope spec.
Beam says a Little League mound takes about 1/3 the clay, 13 bags per inch of depth; Beacon’s ProBrick count for the table and front slope of a 6″ mound is 106 bricks at 2.5″ depth. NC State suggests portable mounds when labor is limited and the field hosts different youth age groups. Ballfields.com says clay is not a good option without water at the field, and a rubber or artificial mat may be better when a couple of parent-coaches are the grounds crew. Portable mound sources: True Pitch, Victory Mounds and ProMounds; Sportsfield Specialties also lists pitching mounds.
Bricks, blocks or loose clay?
| Option | What the source says |
|---|---|
| Beam clay bricks | About 14 bricks = one 50 lb bag compacted (“you are paying to ship water”); bricks are 2-3/8″ thick vs 4–6″ of installed clay |
| Beacon ProBrick | 2.5″ tall; dig 3″; lay tight with alternating seams |
| Turface MoundMaster | Place 10″ before the shortest stride and 10″ wider than the longest landing foot |
| DuraEdge ProLoc | Horizontal at 2.5″ or vertical at 4″ |
| Beam polyurethane pads | Permanent, set 2″ below the surface; Beam says they cut 95% of maintenance there |
Common mistakes
- Rubber in the center. “Too often, the rubber is accidentally placed in the center of the pitcher’s mound” (Cook).
- Height from the grass instead of home plate (Cook, NC State).
- Infield mix in wear areas. Beam: it won’t be firm enough.
- Thick, dry lifts or conditioner between layers. Cook: conditioner keeps layers from bonding.
- Sweeping top-dressing into repairs. Beam: sweep it aside; mixed in, it weakens the clay.
- No tarp or water. Profile calls the tarp “essential”; Joey Stevenson (Indianapolis Indians) reserves high-clay gumbo for facilities with a mound tarp and water.
Keeping it right after the build
Cook repairs after every practice and game, Boettcher patches after every use, and DiVito tarps every day. Recheck the slope with a gauge. Before winter, DiVito insulates the top and landing area, then tarps, to minimize heaving. More in our mound clay guide and tarps guide.
Who can build it or sell you the materials
Before hiring, read how to choose a field builder and the questions to ask before hiring a contractor.
Contractors: Northeast & Mid-Atlantic
- Greenway Athletic Field Services (CT, NY): mound construction
- Thomas Field Solutions (NY, VT, NH, MA, CT, ME): mound construction
- Vance’s Landscape Supply (PA, OH, WV): mound rebuilds, infield clay mixes
- Sports Field Services LLC (NJ): mound and plate rebuilds, volunteer workshops
- Capitol Sports Fields (DC, MD, Northern VA): mound rebuilds
- Mountaineer Diamond Care & Landscaping (DE): mound and plate restoration
- Metro Grounds Management (MD, DC, VA): mound repair
Contractors: Southeast & South
- Sports Turf Services (GA): mound and plate rebuilds
- Athletic Field Services of Arkansas: mound and plate rebuilds
Contractors: Midwest
- Field Source Ohio: mound and plate rebuilding
- Sports Turf Management of Michigan: mound renovation; supplies DuraEdge, Diamond Pro, Pro’s Choice
- Midwest Field Solutions (Chicago): mound and plate construction
- Van’s Enterprises (IL, WI): loose-fill clay and clay-brick mounds
- Professional Outdoor Solutions (IL): rebuilds to specification with professional mound clay
- BallField Renovations (IN): mounds built with clay pavers
- Diamond Doctors of Iowa: mound construction; Pitch Pro portable mound dealer
- Iowa Sports Turf: mound and plate construction
- Mack Bros Sports Construction (NE): mound construction and repair, mound covers
Contractors: Mountain West & West
- Rocky Mountain Sports Fields (CO): mound and bullpen builds to league spec
- All-American Sports Materials (CO): mound construction, bulk clays
- True Hop Field Co. (AZ): mound construction
- Great Fields Co. (CA): regulation mound builds, crew training
- Athletic Field Design (OR): mounds on natural and synthetic surfaces
- Final Cut Turf & Recreation (ID): synthetic turf mounds
Mound clay makers
- Beam Clay: mound and plate clay; MLB supplier
- DuraEdge Products: engineered infield mixes, mound clays
- Turface Athletics: conditioners and mound clays
- Diamond Pro: mound and home plate clays
- Mar-Co Clay Products: mound clay and packing clay bricks
- Southern Baseball Fields: Mar Mound Clay, a red packing clay
- Stabilizer Solutions: Hilltopper Waterless Mound Clay
- Pro’s Choice: Pro Mound for mounds and batter’s boxes
Portable mounds and mound tools
- True Pitch: portable mounds, Flex-A-Clay packing clay, rubbers
- Victory Mounds: portable mounds, groundskeeper supplies
- ProMounds: portable game and practice mounds
- Sportsfield Specialties: pitching mounds, plate and base systems
- Beacon Athletics: mound covers, tarps, clays, maintenance training
Find mound clay and bricks in our directory of mound and plate clay suppliers and get delivered pricing before you build.
Once the mound is built, the rest of the diamond needs its lines. See our guide to baseball and softball field marking for what a striping service costs and how to lay out lines yourself.
