Shed Base Gravel Calculator
Estimate the gravel for a shed foundation pad. Enter the pad's length, width and depth to get cubic yards, tons and cost — pre-set to a 4-inch crushed-stone base, sized for a 10 × 8 shed with a 1-foot margin.
Sets a typical depth — tweak anything below.
For a 12 ft × 10 ft area at 4 in deep, order about 1.63 cubic yards (2.2 US tons) of crushed stone.
Estimates only. Densities vary by moisture, compaction and supplier — confirm quantities before ordering.
How much gravel do I need for a shed base?
Work out the pad size first (it's bigger than the shed — see below), then multiply length × width × depth in feet and divide by 27 for cubic yards. A 12 ft × 10 ft pad at 4 inches deep is about 1.5 cubic yards, or 2 tons of crushed stone. Most shed pads land between 1 and 4 yards, which is right at the point where a bulk delivery beats bags. Enter your pad above for the exact figure.
How big should a shed gravel pad be?
Make the pad extend at least 1 foot past the shed on every side. This is the step almost everyone skips, and it's why so many shed pads fail. A shed has no gutters, so every rainfall dumps a line of water off the roof edge straight down. If the gravel stops at the wall, that water lands on soil right at the pad's edge and washes it out, undercutting the corner your shed is standing on. Running the stone a foot past the wall gives the runoff something to land on and drain through. So a 10 × 8 shed wants a 12 × 10 pad — that's 20 square feet more than the shed's own footprint, and it's the difference between a base that lasts and one that slumps in two years.
How deep should a shed base be?
4 inches of compacted stone is standard for a garden shed on firm ground. Go to 6 inches for a big shed, a workshop with equipment in it, or soft and clay soils. Compact it — a plate compactor is a cheap day rental and it's what turns a pile of loose stone into a foundation. Check the pad is level in both directions before the shed goes on: a shed built on a pad that isn't level will have doors that jam and won't latch, and that's very hard to fix once the building is up.
What gravel for a shed foundation?
Two good answers, depending on whether you frame the pad. Crushed stone or #57 in a timber frame is the classic build: the frame holds the stone in place, and #57 drains freely so the shed floor stays dry. Compacted road base works too and packs harder, but it holds more water — better under a shed that sits on skids or blocks. What doesn't work is pea gravel or any rounded stone: it never locks together, so the shed settles unevenly into it. Whatever you use, lay landscape fabric under it to stop the stone sinking into the soil.
Shed pad size guide
| Shed size | Pad size (+1 ft each side) | Gravel at 4 in |
|---|---|---|
| 6 × 4 ft | 8 × 6 ft | ≈ 0.6 cu yd · 0.8 tons |
| 8 × 6 ft | 10 × 8 ft | ≈ 1 cu yd · 1.3 tons |
| 10 × 8 ft | 12 × 10 ft | ≈ 1.5 cu yd · 2 tons |
| 12 × 10 ft | 14 × 12 ft | ≈ 2.1 cu yd · 2.8 tons |
| 16 × 12 ft | 18 × 14 ft | ≈ 3.1 cu yd · 4.2 tons |
Pad runs 1 ft past the shed on all sides so roof runoff lands on stone, not on the soil at the pad's edge.
Worked examples
- 10 ft × 8 ft = 80 sq ft
- 80 × 4 in (0.33 ft) = 26.7 cu ft
- 26.7 ÷ 27 = 0.99 cubic yards
- × ~1.35 ton/yd³ ≈ 1.3 tons
- 12 ft × 10 ft = 120 sq ft
- 120 × 4 in (0.33 ft) = 40 cu ft
- 40 ÷ 27 = 1.48 cubic yards
- × ~1.35 ton/yd³ ≈ 2 tons
- 14 ft × 12 ft = 168 sq ft
- 168 × 6 in (0.5 ft) = 84 cu ft
- 84 ÷ 27 = 3.1 cubic yards
- × ~1.35 ton/yd³ ≈ 4.2 tons
Common mistakes to avoid
- Making the pad the same size as the shed. A shed has no gutters. Runoff off the roof edge washes out soil right at the pad's edge and undercuts it. Run the stone 1 ft past every wall.
- Not compacting. Loose stone isn't a foundation — the shed settles into it unevenly. Compact in layers with a plate compactor; it's a cheap day rental.
- Using pea gravel or round stone. Rounded stone never locks together, so the shed sinks unevenly. Use angular crushed stone, #57, or compacted road base.
- Not checking level before the shed goes up. A pad that's out of level gives you doors that jam and won't latch — and it's very hard to fix once the shed is standing on it.
- Skipping the fabric. Straight on soil, the stone works its way into the ground and the pad thins out. Landscape fabric under the base keeps it separated.
Frequently asked questions
How much gravel do I need for a shed base?+
A 12 ft × 10 ft pad (right for a 10 × 8 shed) at 4 inches deep needs about 1.5 cubic yards, roughly 2 tons of crushed stone. Enter your pad size above for the exact amount.
How big should a shed gravel pad be?+
At least 1 foot bigger than the shed on every side — so a 10 × 8 shed gets a 12 × 10 pad. Sheds have no gutters, and the extra stone catches the roof runoff that would otherwise wash out the soil at the pad's edge and undercut it.
How deep should a gravel shed base be?+
4 inches of compacted stone for a normal garden shed on firm ground; 6 inches for a large shed, a workshop, or soft and clay soil.
What gravel is best for a shed foundation?+
Crushed stone or #57 held in a timber frame — #57 drains freely so the floor stays dry. Compacted road base also works and packs harder. Avoid pea gravel and other rounded stone, which never locks together and lets the shed settle unevenly.
Do I need a frame around the shed pad?+
It's not required but it's worth it, especially with clean stone like #57 that has no fines to hold it together. A pressure-treated timber frame keeps the pad's edges crisp and stops the stone spreading out over time. Without a frame, use a stone with fines that packs, and expect to tidy the edges occasionally.