Gravel for 20 × 20 ft by depth
| Depth | Cu ft | Cu yd | Tons, gravel | Tons, crushed stone | 0.5 cu ft bags |
|---|---|---|---|---|---|
| 2 in | 67 | 2.47 | 3.50 | 3.70 | 134 |
| 3 in | 100 | 3.70 | 5.25 | 5.56 | 200 |
| 4 in | 133 | 4.94 | 7.00 | 7.41 | 267 |
| 6 in | 200 | 7.41 | 10.5 | 11.1 | 400 |
| 8 in | 267 | 9.88 | 14.0 | 14.8 | 534 |
| 12 in | 400 | 14.8 | 21.0 | 22.2 | 800 |
Gravel at 1.42 t/yd³ (Engineering ToolBox); crushed stone at 1.50 t/yd³ (Hello Gravel). No extra added.
Rochester Concrete Products' install guide adds 10% for compaction and uneven ground. A 20x20 pad is a common size for a shed, hot tub or patio; see the project calculators for the depth each one calls for.
Working it out
400 sq ft × depth (in) ÷ 12 ÷ 27 = cubic yards
At 4 inches: 400 × 4 ÷ 12 = 133.3 cubic feet, ÷ 27 = 4.94 cubic yards. Multiply by the weight per cubic yard of your stone to get tons.
Common questions
How many yards of gravel for a 20x20 area at 3 inches?
3.70 cubic yards, about 5.25 tons.
How many bags of gravel for a 20x20 area?
At 2 inches deep, 134 bags of 0.5 cu ft; at 4 inches, 267.
Related calculators
Sources
- https://www.engineeringtoolbox.com/dirt-mud-densities-d_1727.html
- https://hellogravel.com/guides/2025-gravel-prices-per-ton-delivered-cost-calculator-and-regional-rates/
- https://www.doitbest.com/product/276837/
- https://rochestercp.com/resources/installation-manuals/installation-manual-vintage-6.pdf