Road Base Calculator
Calculate tons of road base needed for a driveway or pad at your depth, using its 1.5 tons per cubic yard compacted density.
How this calculator works
Road base is priced and delivered by the ton, so this calculator converts your area and depth into cubic yards, then multiplies by road base’s compacted density of 1.5 tons per cubic yard — the same density used for crusher run, since both are graded aggregate-and-fines mixes.
Formula: Cubic yards = (Length ft × Width ft × Depth ft) ÷ 27. Tons = Cubic yards × 1.5.
Worked example
A 20 ft × 10 ft driveway section at a 6-inch depth:
- Depth in feet: 6 ÷ 12 = 0.5 ft
- Cubic yards: (20 × 10 × 0.5) ÷ 27 ≈ 3.704 yd³
- Tons: 3.704 × 1.5 ≈ 5.56 tons
- At $35/ton, that’s $194.44 before waste.
Coverage reference
| Depth | Coverage per ton |
|---|---|
| 4 in | ~54 sq ft |
| 6 in | ~36 sq ft |
| 8 in | ~27 sq ft |
How to measure your area
Measure the full length and width of the driveway or pad footprint, including a few extra inches of width on each side if the base needs to extend past the visible edge of the finished surface. Use the compacted target depth from your project’s spec, not the loose depth you’ll spread before compacting.
Frequently asked questions
What is road base made of?
Road base is a graded mix of crushed aggregate and fines, similar in composition to crusher run — the fines fill the voids between larger stones so the material compacts into a hard, stable layer capable of carrying vehicle loads.
How is road base different from crusher run?
They're functionally very similar and share the same 1.5 tons per cubic yard compacted density. "Road base" is the term more often used for engineered aggregate specified in driveway, road, and pad construction, while "crusher run" is the more general name for the same type of graded stone-and-fines mix sold at most quarries.
How deep should a road base layer be?
4-6 inches is typical under a residential driveway. Areas carrying heavier vehicles, like a parking pad or a section supporting delivery trucks, often call for 8 inches or more, usually compacted in separate lifts rather than one thick pour.
Do I need multiple lifts to compact road base properly?
Yes, once you go beyond about 4 inches. Compacting a single thick lift often leaves the bottom portion under-compacted, since a plate compactor's energy doesn't fully penetrate deep material. Spreading and compacting in 3-4 inch lifts gets a denser, more uniform base.
Can road base go directly under concrete?
Yes — a compacted road base layer is a standard sub-base under concrete slabs and driveways, providing drainage and a stable, load-bearing surface so the concrete doesn't crack or settle unevenly over soft native soil.
Should I add waste when ordering road base?
Yes, the 10% waste toggle accounts for compaction settling, an uneven excavated subgrade, and spillage during spreading — all of which are common on base-layer jobs.
Estimates only. Verify quantities with your supplier before purchasing.