How much road base do I need?
Road base is a mix of crushed rock and fines that packs hard under driveways, roads, slabs, and parking pads.
Enter the length, width, and depth of your area above. The calculator shows cubic yards, cubic feet, an estimated weight in tons, and the number of bags if you buy bagged road base. Add a price per cubic yard and it also estimates the cost.
Cubic yard calculator for road base
This cubic yard calculator for road base works for any shape. Pick rectangle for most beds and slabs, circle for round areas, or trench for narrow runs. Open the price estimator under the calculator to add your supplier price, delivery fee, and tax. For a full cost breakdown, see the cubic yard price estimator.
Road Base weight and bags per cubic yard
A planning value for road base is 2,900 pounds per cubic yard, which is 1.45 US tons. Moisture, particle size, and compaction move that number, so treat it as a starting point.
| Measure | Value |
|---|---|
| Pounds per cubic yard | 2,900 |
| US tons per cubic yard | 1.45 |
| Kilograms per cubic yard | 1,315 |
| Cubic yards per US ton | 0.69 |
| Cubic feet per US ton | 18.62 |
How far does a cubic yard of road base go?
Coverage depends only on depth. The deeper the layer, the less area a cubic yard covers. The suggested depth for road base is 4 to 8 inches, and 6 inches is a common choice.
| Depth (inches) | Square feet covered | Square yards covered |
|---|---|---|
| 1 | 324 | 36.0 |
| 2 | 162 | 18.0 |
| 3 | 108 | 12.0 |
| 4 | 81 | 9.0 |
| 6 | 54 | 6.0 |
| 8 | 40 | 4.5 |
| 12 | 27 | 3.0 |
Road Base needed for common areas at 6 inches deep
| Area | Square feet | Cubic yards | US tons |
|---|---|---|---|
| 5 by 5 ft | 25 | 0.46 | 0.67 |
| 8 by 10 ft | 80 | 1.48 | 2.15 |
| 10 by 10 ft | 100 | 1.85 | 2.69 |
| 10 by 20 ft | 200 | 3.70 | 5.37 |
| 12 by 12 ft | 144 | 2.67 | 3.87 |
| 15 by 20 ft | 300 | 5.56 | 8.06 |
| 20 by 20 ft | 400 | 7.41 | 10.74 |
| 20 by 30 ft | 600 | 11.11 | 16.11 |
| 30 by 40 ft | 1,200 | 22.22 | 32.22 |
| 50 by 50 ft | 2,500 | 46.30 | 67.13 |
Worked example: 40 by 12 feet at 6 inches
The area is 40 feet times 12 feet, or 480 square feet. A depth of 6 inches is 0.50 feet. Volume is 480 times 0.50, which is 240.00 cubic feet. Divide by 27 to get 8.89 cubic yards. At 2,900 pounds per cubic yard that weighs about 12.89 US tons. With 10 percent extra, order 9.78 cubic yards.
Tips for ordering road base
- Build the base in lifts of about 4 inches and compact each lift.
- Extend the base a foot beyond the finished surface for edge support.
- Moisten the material before rolling so it compacts evenly.
Compacted base is denser than the loose material delivered, so order roughly 15 to 25 percent more than the finished volume.
Frequently asked questions
How many cubic yards of road base do I need?
Multiply length, width, and depth in feet, then divide by 27. A 40 by 12 foot area at 6 inches deep needs about 8.89 cubic yards.
How much does a cubic yard of road base weigh?
About 2,900 pounds, or 1.45 US tons, as a planning value. Ask your supplier for the exact figure.
How deep should road base be?
Most projects use 4 to 8 inches. 6 inches is a common choice.
How many square feet does a cubic yard of road base cover?
54 square feet at 6 inches deep, and 324 square feet at 1 inch.