How to calculate a shed base gravel
A compacted gravel pad keeps a shed dry and level, and it needs to extend a bit past the shed walls.
- Measure the shed footprint and add 1 foot on every side.
- Use 4 to 6 inches of compactable stone.
- Calculate the volume and add 10 to 15 percent for compaction.
- Level and compact the pad before setting the shed.
Worked example
For a typical shed base gravel with length 12 ft, width 10 ft, depth 4 in, the volume is 40.00 cubic feet. Divide by 27 for 1.48 cubic yards. With a 10 percent allowance, plan for 1.63 cubic yards.
In crushed stone, 1.48 cubic yards weighs about 2.00 US tons at a planning value of 2,700 pounds per cubic yard.
Shed Base Gravel sizes and quantities
These common sizes are calculated with the same formula as the tool above, so you can find your number quickly.
| Size | Cubic feet | Cubic yards | With 10 percent extra | US tons |
|---|---|---|---|---|
| 8 by 8 ft, 4 in | 21.33 | 0.79 | 0.87 | 1.07 |
| 10 by 12 ft, 4 in | 40.00 | 1.48 | 1.63 | 2.00 |
| 12 by 16 ft, 6 in | 96.00 | 3.56 | 3.91 | 4.80 |
| 16 by 20 ft, 6 in | 160.00 | 5.93 | 6.52 | 8.00 |
Tips
- Timber borders hold the stone and add a tidy look.
- Fabric under the stone blocks weeds.
- Check the shed maker for the recommended base.
Common mistakes to avoid
- Making the pad exactly the shed size.
- Skipping compaction.
- Not sloping the pad away for drainage.
These figures are planning estimates. Real material varies in moisture, size, and compaction, so confirm weights and order quantities with your supplier.
Frequently asked questions
How many cubic yards do I need for a shed base gravel?
Multiply the dimensions in feet and divide by 27. The example above, length 12 ft, width 10 ft, depth 4 in, needs 1.48 cubic yards before waste.
How much extra should I order?
Add 5 to 10 percent for waste. Add more if the ground is uneven or the material is loose.
Can I enter inches and feet together?
Yes. Each box has its own unit selector, so you can mix feet and inches.
How much does shed base gravel material weigh?
1.48 cubic yards of crushed stone weighs about 2.00 US tons as a planning value.