Shed Foundation Calculator
Estimate preliminary shed foundation blocks, skid length, gravel volume, gravel weight and material cost for a rectangular shed base.
Default project preview
12 blocks
Gravel volume
1.63 yd³
Gravel weight
2.28 short tons
Total skid length
36 ft
Foundation footprint
120 ft²
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Input and output guide
What each value means
The labels and units below are part of this calculator’s visible methodology. Replace every default with measurements or product data from the actual project.
Shed length
Enter this project assumption in ft. The current imperial default is 12 ft.
Shed width
Enter this project assumption in ft. The current imperial default is 10 ft.
Foundation skids
Enter this project assumption in a unitless value. The current imperial default is 3. Minimum: 1.
Maximum block spacing
Enter this project assumption in ft. The current imperial default is 4 ft.
Gravel depth
Enter this project assumption in in. The current imperial default is 4 in.
Gravel allowance
Enter this project assumption in %. The current imperial default is 10 %. Minimum: 0. Maximum: 50.
Compacted gravel density
Enter this project assumption in tons/yd³. The current imperial default is 1.4 tons/yd³.
Price per foundation block
Enter this project assumption in a unitless value. The current imperial default is 8. Minimum: 0.
Gravel price per weight
Enter this project assumption in per ton. The current imperial default is 55 per ton. Minimum: 0.
How to read the outputs
Gravel volume
allowance included. Default preview: 1.63 yd³.
Gravel weight
entered compacted density. Default preview: 2.28 short tons.
Total skid length
all skids. Default preview: 36 ft.
Foundation footprint
shed plan area. Default preview: 120 ft².
Block spacing guide
maximum entered spacing. Default preview: 4 ft.
Material cost
blocks and gravel. Default preview: $221.48.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Blocks per skid = round up (shed length ÷ maximum spacing) + 1. Gravel volume = footprint × depth × allowance, then converted to entered density.
Reviewed project guidance
How to use this estimate in a real project
Last reviewed: August 19, 2026
Estimate preliminary shed foundation materials from shed footprint and the selected foundation type, such as gravel pad, skids or discrete supports.
Calculation steps
- 1Select the foundation method actually being planned.
- 2Measure the required foundation footprint, including any designed extension beyond the shed.
- 3Apply the relevant depth, spacing or support count for that method.
- 4Convert the result to supplier units without mixing gravel volume with skid or pier counts.
Worked numerical example
A 10 ft × 12 ft gravel pad extended 1 ft beyond the shed on all sides measures 12 ft × 14 ft. At 4 in compacted depth, it requires about 56 ft³, or 2.07 yd³, of compacted gravel before delivery/compaction adjustment.
Purchasing and rounding
Order each foundation component in its own unit: gravel by volume/mass, skids by length and blocks/piers by count. Do not combine unlike materials into a single generic package-yield calculation.
Interpret the result
The result is a material quantity for the selected foundation method. Soil bearing, frost depth, anchorage and local code requirements determine whether that method is appropriate.
Page-specific assumptions
- The foundation type and dimensions are known before quantity calculation.
- Gravel depth is compacted depth where gravel is used.
- Structural support spacing comes from the shed/foundation design.
Common mistakes
- Using shed floor area without required pad overhang.
- Treating loose-delivered gravel as equal to compacted volume.
- Mixing several foundation methods in one calculation.
- Ignoring frost or anchorage requirements.
Primary and technical references
BuildMeter provides planning estimates, not engineering, architectural, electrical, mechanical, plumbing, permit or code approval. Review the methodology and verify final decisions with product documentation and qualified professionals.
BuildMeter Guides
Understand the measurements and assumptions
Use these visible reference guides before changing project inputs or planning allowances.
FAQ
Shed Foundation Calculator questions
Can blocks be placed directly on soil?+
A compacted, drained base is commonly used, but the approved foundation method depends on site and local requirements.
Does this size the skids?+
No. Skid size and span require structural selection.
Is anchoring included?+
No. Wind anchorage and tie-down details are separate from this quantity estimate.