Enter shed length and width.
Calculate a compacted stone pad for a storage shed, workshop, or small outbuilding. Enter the full pad dimensions, including the recommended perimeter beyond the shed walls.
Verified formulaEditable presetsUS + metric
Purpose-built estimator
Project measurements
The outside length of the shed footprint.
The outside width of the shed footprint.
Extra gravel pad beyond each shed side.
Finished compacted stone thickness.
Bulk density for shed foundation stone.
Extra loose stone for compacted pad depth.
Percent added for cuts, spillage, edge cleanup, and small estimating errors.
Optional supplier price used to estimate material cost before delivery fees and taxes.
Shed pad plan and section
- 1Shed footprint
- 2Pad extension
- 3Compacted stone
- 4Level subgrade
How to use this calculator
Read full measuring guide Measure, verify, and order
Start with the shed footprint, add the required overhang on every side, then calculate the compacted stone layer.
Choose pad extension per side.
Review the expanded pad footprint.
What each input means
Shed length
The outside length of the shed footprint.
Unit: ft or m. Use the shed manufacturer floor or skid length.Shed width
The outside width of the shed footprint.
Unit: ft or m. Measure the narrow side of the shed footprint.Pad extension per side
Extra gravel pad beyond each shed side.
Choose the shed supplier requirement or local practice.Compacted pad depth
Finished compacted stone thickness.
Unit: in or cm. Measure excavation depth below finished pad grade.Stone density
Bulk density for shed foundation stone.
Unit: lb/ft3 or kg/m3. Use supplier density or a local tons-per-yard quote.Compaction allowance
Extra loose stone for compacted pad depth.
Unit: percent. Use the compaction allowance from supplier or installer.Extra / waste
Percent added for cuts, spillage, edge cleanup, and small estimating errors.
Unit: percent. Use 5 percent for simple square work and 10 percent or more for irregular work.Price per ton
Optional supplier price used to estimate material cost before delivery fees and taxes.
Unit: USD per US ton. Enter the quoted material price per US short ton. Leave 0 if you only need quantity.Check the calculation
Example: a 10 ft by 12 ft shed with 6 inches per side becomes an 11 ft by 13 ft gravel pad.
A 12 × 16 ft pad at 4 inches deep needs 2.37 compacted cubic yards before compaction and waste allowances.
Total loose order 2.16 cu yd Total weight 2.91 US tons
Pad length = shed length + 2 x overhang. Pad width = shed width + 2 x overhang.
Assumptions to check
- Make the pad about 12 inches wider than the shed on each side.
- Excavate organic soil and use geotextile where appropriate.
- Confirm foundation requirements with the shed manufacturer.
- Does not design footings or anchors.
- Weak soil may need geotextile or a deeper base.
- Always follow shed manufacturer instructions.
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Frequently Asked Questions
What does this shed foundation gravel calculator calculate?
It uses project-specific inputs and the formula shown below. Pad length = shed length + 2 x overhang. Pad width = shed width + 2 x overhang.
Are the presets exact specifications?
No. Presets are editable planning starting points. Confirm depths, materials, and densities with the supplier, manufacturer, or project designer.
Why can delivered weight differ?
Bulk density varies by supplier and moisture level. Moisture, gradation, compaction, and scale accuracy can change the delivered weight.