Shed Material Calculator — Complete Lumber & Materials List
Calculate all materials needed to build a shed: floor framing, wall studs, roof rafters, sheathing, roofing, siding, and hardware. Supports gable, gambrel, and lean-to roof styles.
How to Use This Calculator
- Enter your shed dimensions: length, width, and wall height
- Select the roof style and pitch
- Choose your siding type
- Enter the number of doors and windows
- Click "Calculate Shed Materials" for a complete lumber and materials list
How the Calculation Works
// Floor
floor_joists = ceil(width_ft / (joist_spacing_in / 12)) + 1
// Walls
wall_studs_per_wall = ceil(wall_length_ft / (stud_spacing_in / 12)) + 1
total_studs = (front + back + 2 sides) × studs_per_wall + corners + headers
// Roof (gable)
rafter_length = (width_ft / 2) / cos(pitch_angle) + overhang
total_rafters = ceil(length_ft / (rafter_spacing_in / 12)) × 2 + 2
// Sheathing
floor_sheets = ceil((length_ft × width_ft) / 32)
wall_sheets = ceil(total_wall_area_sqft / 32)
roof_sheets = ceil(roof_surface_area_sqft / 32) Floor joists span the width of the shed at the selected spacing. Wall stud counts include regular studs plus double top plate, single bottom plate, and extra studs at corners and door openings. Rafter length is calculated using the roof pitch angle and the half-span, plus overhangs. All sheathing (floor, walls, roof) is estimated in 4×8 sheets (32 sq ft each). A waste factor is applied to all sheet goods.
Variables:
- floor_joists: Number of floor joists spanning the shed width
- total_studs: Total wall studs including corners and door opening framing
- rafter_length: Length of each roof rafter including overhang
- total_rafters: Total number of roof rafters (both sides for gable)
- floor_sheets: 4×8 sheets of 3/4" plywood or OSB for the floor deck
Pro Tips
- Use pressure-treated lumber for all floor framing — joists, rim joists, and skids that contact the ground
- Standard shed stud spacing is 16" on-center for walls; 24" OC is acceptable for sheds under 200 sq ft
- A 12/12 pitch gambrel roof maximizes headroom and storage; a 4/12 gable is simpler to build
- Pre-hung shed doors typically need a rough opening 2" wider and 1.5" taller than the door size
- Add a drip edge all around the roof perimeter — it is inexpensive and prevents significant water damage
Recommended Products
Frequently Asked Questions
How much does it cost to build a shed?
Material costs for a DIY shed vary widely: a 8×10 shed runs $800–$2,000 in materials; a 12×16 shed typically costs $2,000–$5,000 in materials depending on quality of lumber, siding, and roofing. Labor costs for a contractor-built shed add 50–100% to material cost. Shed kits are priced competitively but quality varies.
Do I need a permit to build a shed?
Permit requirements vary by municipality. Many jurisdictions exempt accessory structures under 200 sq ft (some say 120 sq ft) that are not connected to utilities. Always check with your local building department before construction. Even if no permit is required, there are typically setback requirements (distance from property lines and other structures).
What size shed do I need?
For basic lawn equipment: 8×8 or 8×10. For a riding mower plus tools: 10×12 or 12×12. For a full workshop: 12×16 or 12×20 minimum. Allow extra space for workbench, shelving, and moving around — a shed that fits everything still feels cramped if there is no aisle space. Many people wish they built larger.
What is the best foundation for a shed?
Concrete piers or deck blocks are easiest for small sheds and allow airflow under the floor. A gravel pad with concrete blocks is better for larger sheds and prevents moisture. A full concrete slab provides the most durability and is required by some codes. Pressure-treated skids on a gravel pad are popular for portable or temporary sheds.
What roof pitch is best for a shed?
A 4/12 to 6/12 pitch is standard for most sheds — it sheds water well, is easy to frame, and is not too steep to work on. A 12/12 gambrel (barn-style) roof dramatically increases usable headroom and loft storage. A lean-to (1/12 to 3/12) is the simplest to build but requires the shed to drain away from the attached structure.