Road Base Calculator
Road base (crusher run, DGA) is ordered loose: length × width × the finished compacted depth, plus about 15% because the base loses volume when rolled. A 20 × 20 ft slab base at 4 in compacted is 4.94 yd³ — order about 5.7 yd³, or roughly 10.1 tons. For the gravel surface on top, use the Gravel Driveway Calculator.
How it's calculated: Order volume = length × width × compacted depth × 1.15; weight = volume × ≈ 2,100 kg/m³ (≈ 1.77 US tons per yd³).
Result appears here
Fill in the fields and press Calculate.
Formula, calculation, assumptions and sources
Volume = Length × Width × Depth
Weight = Volume × bulk density
Run the calculation to see each step with your own numbers.
A 20 ft × 20 ft slab sub-base, 4 in compacted, 15% for compaction.
Compacted volume = 133 ft³ = 4.94 yd³
Weight ≈ 4.94 × 1.77 ≈ 8.74 US tons
Order loose (+15%): 5.68 yd³ / 10.06 tons
- The depth you enter is the FINISHED compacted depth; the waste allowance converts it to the loose volume you order.
- Dense-graded aggregate base (crusher run / DGA / ABC) at ~140 lb/ft³ compacted.
- A rectangular sub-base area at one uniform depth; for a curved or flared driveway, break it into rectangles.
- Do I enter loose or compacted depth?
- Enter the finished compacted depth you want. The 15% allowance converts it to the loose volume you order, because base material is delivered loose and loses volume when rolled.
- What is crusher run / ABC / DGA?
- Different regional names for the same thing: a dense-graded blend of crushed stone and stone dust that locks together hard when compacted. It's the standard base under a driveway, slab or paver patio, not a finish surface.
- How much road base do I need?
- Multiply length × width × the finished compacted depth in feet, divide by 27 for cubic yards, and add about 15% for compaction. A 20 × 20 ft area at 4 in needs 4.94 yd³ compacted, or about 5.7 yd³ ordered.
- How many tons of crusher run are in a cubic yard?
- Roughly 1.75–1.8 US tons per cubic yard at the ≈ 2,100 kg/m³ compacted density the calculator uses. A 20 × 20 ft base at 4 in compacted is about 8.7 tons, or 10.1 tons with the 15% allowance.
Volume
Standard geometry: Volume = L × W × D. Unit conversions per NIST SP 811.
Bulk density
Compacted dense-graded aggregate base ≈ 2,100–2,200 kg/m³ (≈140 lb/ft³). State-DOT base-course specifications.
About the Road Base Calculator
The Road Base Calculator sizes the dense-graded aggregate (crusher run, ABC, DGA) that forms the compacted sub-base under a driveway, slab or paver installation. Enter the finished compacted depth you want — the waste allowance converts it to the larger loose volume you actually order, because base material loses 15–20% of its bulk when it is rolled. The surface course above it is a separate calculation.
What you enter
- Length
- Width
- Depth — 4 in for a residential driveway or paver base; 6–8 in for heavier traffic or poor soil.
- Waste allowance — Default 15%. Adjust to your own allowance — the exact figure is always shown too.
What you get back
- Volume — shown as the exact figure and, separately, a recommended figure with your waste allowance added.
- Delivered weight — Suppliers usually sell by weight. Weight uses a typical compacted density for dense-graded base (≈ 2,100 kg/m³) — confirm the tons-per-yard with your supplier.
The formula, a worked example, the assumptions behind it and the sources are shown in full below the calculator.
Related calculators
- Gravel Driveway Calculator — Gravel for a driveway of a given length, width and depth, by layer.
- Crushed Stone Calculator — Crushed stone by volume and weight. Shares the density question with the Gravel Calculator.
- Asphalt Calculator — Hot-mix asphalt tonnage for a paved area and thickness.
- Paver Sand Calculator — Bedding sand for a paver installation.
- Gravel Calculator — Gravel by volume and by delivered weight for driveways, paths and fill.
Related articles
- Road Base Materials Explained — Road base is typically a graded mix of crushed stone sizes down to fines, engineered to compact densely and distribute loads from the surface above.
Part of the Landscaping & Driveway calculators.