Road Base Calculator
Tons, cubic yards, and coverage for compacted road base and aggregate base course projects. Use it for residential driveways, parking areas, and subbase under slabs. Choose from standard ABC, recycled concrete, recycled asphalt, crushed granite, or custom density. Presets fill in common depths for driveways, heavy duty parking, and slab subbase work.
Results
Densities are compacted in-place values from USACE and FHWA aggregate base course standards. Order quantities from the calculator are direct order tonnages, so no separate adjustment for compaction loss is needed, unlike loose-delivery aggregates where 15 to 20 percent additional volume covers compaction. Verify exact density and minimum delivery quantity with your supplier. Local specs (Caltrans Class 2, Colorado Class 6, state DOT) may dictate specific material types and compacted thicknesses for permitted work.
How to use this calculator
- 01Pick an application: residential driveway, heavy-duty driveway or parking lot, sub-base under concrete slab, or custom. The depth field auto-fills with a recommended compacted depth.
- 02Pick a material: Standard ABC (140 lb/ft³ compacted), recycled concrete (RCA), recycled asphalt (RAP), crushed granite, or custom density for a supplier-quoted value.
- 03Pick a shape: rectangle for straight runs, circle for round areas, or custom area for irregular shapes.
- 04Enter your dimensions and adjust depth if needed. Add a waste percentage of 5 to 15 percent to cover spillage and over-order; compaction loss is already built into the density.
- 05Read total tons, cubic yards, and coverage area at the top of the results panel. Add a price per ton for cost estimation.
Understanding the math
Road base tonnage uses standard compacted-density math. Cubic yard volume comes from length, width, and depth in feet, divided by 27. Tonnage comes from volume times material density in pounds per cubic foot, divided by 2000. Waste percentage is added on top to cover spillage during placement and minor over-order to avoid running short. Densities are compacted in-place values, so no separate adjustment for compaction loss is needed. The result is the order quantity you give your supplier.
Volume (ft³) = length × width × depth Volume (yd³) = ft³ / 27 Tonnage (tons) = ft³ × density / 2000 Order quantity = tonnage × (1 + waste / 100)
For a 20 ft × 30 ft residential driveway at 6 in depth using Standard ABC (140 lb/ft³) with 10 percent waste: volume is 20 × 30 × 0.5 = 300 ft³ (11.11 yd³). Tonnage is 300 × 140 / 2000 = 21 tons. With 10 percent waste added, order quantity is 21 × 1.1 = 23.1 tons. Round up to whole tons when calling your supplier.
Road base materials and coverage
Compacted in-place coverage values for the four locked material types. Imperial and metric legs are computed independently from each density anchor, no scaling between systems. Sources: USACE/FHWA aggregate base course standards for Standard ABC density; supplier-quoted bulk compacted densities for RCA, RAP, and crushed granite.
| Material | Use Case | Recommended Depth | Coverage per Ton |
|---|---|---|---|
| Standard ABC (140 lb/ft³) | Sub-base under slab | 4 in | 43 sq ft |
| Standard ABC (140 lb/ft³) | Residential driveway | 6 in | 29 sq ft |
| Standard ABC (140 lb/ft³) | Heavy-duty / parking | 8 in | 21 sq ft |
| Recycled concrete RCA (130 lb/ft³) | Residential driveway | 6 in | 31 sq ft |
| Recycled asphalt RAP (135 lb/ft³) | Residential driveway | 6 in | 30 sq ft |
| Crushed granite (145 lb/ft³) | Residential driveway | 6 in | 28 sq ft |
Frequently asked questions
How much road base do I need?
Multiply length × width × depth in feet to get volume in cubic feet. Divide by 27 for cubic yards. For tonnage, multiply cubic feet by the material density (140 lb/ft³ for Standard ABC) and divide by 2000. Add 5 to 15 percent waste to cover spillage and over-order. The calculator above runs this math for any of the five material options at your selected depth and dimensions.
How much does 1 ton of road base cover?
At 6 inch compacted depth and 140 lb/ft³ density, 1 ton of Standard ABC covers about 29 square feet. At 4 inches it covers about 43 sq ft. At 8 inches, about 21 sq ft. For metric: 1 tonne at 15 cm depth and 2243 kg/m³ density covers about 3 m². These values come from dividing cubic-foot-per-ton (ft³/ton = 2000/density) by the depth in feet.
How much does 1 yard of 3/4 road base weigh?
One cubic yard of compacted 3/4-inch road base weighs about 3780 pounds, or 1.89 tons. This uses the 140 lb/ft³ Standard ABC density × 27 ft³ per yard. Loose-delivery 3/4 road base before compaction runs closer to 2700 to 3000 lb per cubic yard (about 1.35 to 1.5 tons). The calculator uses compacted density throughout for direct supplier ordering.
How thick should a road base be?
Common depths by application: residential driveways 4 to 6 inches, heavy-duty driveways and parking lots 6 to 10 inches, sub-base under concrete slabs 4 inches minimum. Follow local building codes and your specific soil conditions. Heavy commercial work and roadway construction typically uses 8 to 12 inches or more per state DOT specs (Caltrans Class 2, Colorado Class 6, and similar regional standards specify exact compacted thickness).
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