Shed Foundation Calculator
Gravel pad, blocks or slab volume for a shed base.
Enter your values
Enter the shed length in ft.
Enter the shed width in ft.
Enter the pad overhang each side in in.
Enter the gravel depth in in.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Gravel needed
- 1.73 cubic yards
- Gravel weight
- 2.42 tons
- Pad footprint
- 14 x 10 ft
- 4 in concrete slab option
- 1.19 cubic yards
- Concrete blocks (skid base)
- 12
Working
- 114 x 10 x 0.33 ft = 1.73 yd3
Quick answer
A shed pad is normally 12 inches larger than the shed on every side, 4 to 6 inches of compacted gravel, or a 4 inch slab.
pad volume = (L+2) x (W+2) x depth/12
At a glance
| What it does | Gravel pad, blocks or slab volume for a shed base. |
|---|---|
| Category | Home & DIY |
| Inputs needed | Shed length, Shed width, Pad overhang each side, Gravel depth |
| Main output | Gravel needed |
| Formula | pad volume = (L+2) x (W+2) x depth/12 |
| Cost | Free — no sign-up, no download |
How to use the Shed Foundation Calculator
- 1Enter the shed footprint from the manufacturer's spec, not the roof size.
- 2Extend the pad 12 inches past the walls so water drips clear of the base.
- 3Compact the gravel in 2 inch lifts for a base that will not settle.
Inputs explained
- Shed length(ft)
- Enter the shed length in ft.
- Shed width(ft)
- Enter the shed width in ft.
- Pad overhang each side(in)
- Enter the pad overhang each side in in.
- Gravel depth(in)
- Enter the gravel depth in in.
Worked example
Using the values the calculator loads with:
Inputs
- Shed length12 ft
- Shed width8 ft
- Pad overhang each side12 in
- Gravel depth4 in
Results
- Gravel needed1.73 cubic yards
- Gravel weight2.42 tons
- Pad footprint14 x 10 ft
- 4 in concrete slab option1.19 cubic yards
- Concrete blocks (skid base)12
- 14 x 10 x 0.33 ft = 1.73 yd3
Frequently asked questions
Gravel or concrete for a shed base?
Gravel drains, is cheaper and suits most timber sheds. Choose concrete for heavy equipment, vehicles or anything anchored down.
How thick should the gravel be?
4 inches on firm ground, 6 inches on soft or clay soil, compacted in layers.
What do I need to enter into the Shed Foundation Calculator?
Just 4 values: shed length, shed width, pad overhang each side, gravel depth. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Shed Foundation Calculator work out the answer?
A shed pad is normally 12 inches larger than the shed on every side, 4 to 6 inches of compacted gravel, or a 4 inch slab. It applies the formula pad volume = (L+2) x (W+2) x depth/12 and shows the working so you can check each step by hand.
Is the Shed Foundation Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.