How Much Gravel for a Shed Base? 8×10, 10×12 and 12×16 Worked Out
A 10×12 shed on a 4 in gravel pad with a 1 ft border needs about 2.1 cubic yards (roughly 2.9 tons) of gravel. Here are the numbers for three popular sizes and how to adjust them.
The method
A gravel shed base is a shallow box of stone. Its volume is length × width × depth, and you order it in cubic yards or tons. In feet and inches:
Cubic yards = length (ft) × width (ft) × depth (in) ÷ 324 Tons (approx.) = cubic yards × 1.4
The 324 converts inches to feet (÷12) and cubic feet to cubic yards (÷27). The 1.4 is a common planning density for gravel and crushed stone in US tons per cubic yard. The real figure depends on the stone, its grading and how wet it is, so ask your quarry for the weight of the exact product.
How big and how deep?
Two choices drive the quantity:
- Pad size. Many installers make the pad wider than the shed so rain dripping off the roof lands on gravel rather than soil. A 1 ft border on every side is a common choice, and it adds a surprising amount: a 10×12 shed becomes a 12×14 pad, about 40% more area.
- Depth. Gravel pads are commonly 4–6 in deep, but the right depth depends on your soil, drainage and the shed. Your shed manufacturer’s base instructions come first. Some require a specific depth, a timber frame or a concrete slab instead.
Quantities for popular shed sizes
| Shed | Pad | Depth | Cubic yards | Approx. tons (×1.4) |
|---|---|---|---|---|
| 8×10 | 8×10 (no border) | 4 in | 0.99 | 1.38 |
| 8×10 | 10×12 (1 ft border) | 4 in | 1.48 | 2.07 |
| 8×10 | 10×12 (1 ft border) | 6 in | 2.22 | 3.11 |
| 10×12 | 10×12 (no border) | 4 in | 1.48 | 2.07 |
| 10×12 | 12×14 (1 ft border) | 4 in | 2.07 | 2.90 |
| 10×12 | 12×14 (1 ft border) | 6 in | 3.11 | 4.36 |
| 12×16 | 12×16 (no border) | 4 in | 2.37 | 3.32 |
| 12×16 | 14×18 (1 ft border) | 4 in | 3.11 | 4.36 |
| 12×16 | 14×18 (1 ft border) | 6 in | 4.67 | 6.53 |
Worked example: a 10×12 shed
With a 1 ft border the pad is 12 × 14 = 168 ft². At 4 in deep: 168 × 4 ÷ 324 = 2.07 cubic yards, about 2.9 tons at 1.4 tons per yard. In 0.5 ft³ bags, a common size for bagged gravel, that is 2.07 × 27 ÷ 0.5 = 112 bags. At this size a bulk delivery almost always makes more sense than bags.
Metric version
In metric, volume (m³) = length (m) × width (m) × depth (mm) ÷ 1000. A 3 × 3.6 m pad at 100 mm deep is 1.08 m³. Our 1.4 tons-per-yard planning figure works out to about 1.66 tonnes per m³, so that’s roughly 1.8 tonnes. Again, the supplier’s figure for their product beats any rule of thumb. Some UK merchants sell aggregate in bulk bags described by weight, so check what one of their bags actually contains before working out how many to order.
Compaction and the extra you should order
Gravel that is spread and then compacted with a plate compactor or roller ends up thinner than it was spread, because the stones lock together. That means you need more loose gravel than the finished depth suggests. How much more depends on the material, so ask the supplier how much to allow for the product and method you’re using, and add it in the Extra field of the gravel calculator.
Practical tips
- Level first. Strip turf and organic soil, then level the ground before measuring the depth you’ll fill. Uneven ground is the most common reason orders run short.
- Edge the pad. Many pads use a timber frame or edging to hold the gravel; build it to the finished height so it doubles as a depth guide.
- Weed membrane. A permeable landscape fabric under the gravel helps keep weeds down.
- Before you dig, find out what’s underground. In the US, contact 811.
Frequently asked questions
How much gravel do I need for a 10×12 shed?
For a 12×14 pad (1 ft border) at 4 in deep, about 2.07 cubic yards, roughly 2.9 tons at 1.4 tons per yard. Without the border, about 1.48 cubic yards.
How deep should a gravel shed base be?
Gravel pads are commonly 4–6 in deep, but follow your shed manufacturer’s base instructions and adjust for your soil and drainage.
How many tons is a cubic yard of gravel?
About 1.4 US tons is a common planning figure, but it varies with the stone and its moisture. Ask the supplier for the weight of the product you’re buying.
Should the gravel pad be bigger than the shed?
Many installers extend the pad about 1 ft beyond each side so roof run-off lands on gravel. It adds area, so include it before ordering.