By Zencalcy Editorial TeamLast reviewed About us
Shed cost tracks three surfaces: the floor, the walls and the roof. A steeper pitch adds roof area and material, taller walls add siding, and the foundation can rival the frame in price. This calculator prices each surface from a single cost-per-square-foot figure and adds a foundation allowance.
Budget a shed from its footprint, wall height and roof pitch.
Floor = L × W Walls = 2 × (L + W) × H Roof = footprint ÷ cos(pitch) × 1.15
Roof area includes a 15% allowance for overhangs and waste. The pitch multiplier is 1 ÷ cos(atan(rise/12)); a 4/12 pitch adds about 5%, an 8/12 pitch about 20%. Cost per square foot covers framing, siding, roofing and fasteners, not tools or permits.
| Symbol | Meaning |
|---|---|
| L, W | Shed length and width. |
| H | Wall height. |
| c | Cost per square foot of built surface. |
Floor 120 sq ft, walls 352 sq ft, roof about 145 sq ft — 617 sq ft of surface. At $28/sq ft plus a $600 foundation allowance the shed costs roughly $17,900.
Continue with the Gravel Calculator, Sand Calculator, Rock Calculator, or the River Rock Calculator — or browse more materials & quantities and all construction calculators.
Materials typically run $20–40 per square foot of floor area for a simple gable shed, so a 10 × 12 shed is $2,400–4,800 in materials. The surface-based figure here is higher because it counts walls and roof too.
Results use standard construction estimating arithmetic: volumes from measured area and depth, unit weights from published material densities, and code-referenced spans or clearances where the page names a code. Quantities are rounded up to whole saleable units and include the stated waste allowance. These tools are planning aids, not structural design, and do not replace a licensed engineer, a local code check, or a contractor's site measurement.
Reference material used to build and check this calculator:
Last reviewed: September 2026. See how we build and check every tool on the about page.
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Content updated: September 2026