Foundation planning
Shed Foundation Material Calculator
Estimate excavation area, compacted gravel volume and geotextile coverage for a rectangular shed pad.
Calculate a gravel pad from finished dimensions
The calculator adds the selected border to each side of the shed footprint, multiplies pad area by compacted gravel depth and applies a material allowance. It also estimates geotextile coverage and converts cubic feet to cubic yards.
Compacted volume is not loose delivery volume
Gravel settles during placement and compaction, so delivered volume may need to exceed finished compacted volume. Soil bearing capacity, drainage, frost depth and the shed manufacturer’s anchoring requirements can change the correct foundation design.
Use this result after choosing a foundation type in the resin shed foundation guide. Compare complete structures in the garden storage shed guide.
Frequently asked questions
How far should the pad extend?
Follow the shed and foundation instructions; the entered border is a planning value.
Does the bag count include compaction?
It uses the entered allowance, but actual bag yield and compaction vary.
Can a gravel pad replace anchoring?
No. Foundation support and wind anchoring are separate requirements.