Road Base & Gravel Driveway Calculator
Estimate road base volume, weight, and material cost from project dimensions.
Road Base & Gravel Driveway Calculator
Road base calculator results
Compaction allowance is applied before waste; truck loads round up from the selected payload.
Material and project hints
Road base tonnage formula
Base Cubic Yards = Area (sq ft) × Thickness (in) ÷ 324
After compaction allowance = Base Cubic Yards × (1 + Compaction%)
Order quantity = After compaction allowance × (1 + Waste factor%)
Tons = Order quantity × 27 × Unit weight (lb/ft³) ÷ 2,000
Cost = Tons × Price per ton
Road base planning notes & sources
Use a supplier or tested density in the same material state you are estimating. Density converts volume to weight; it does not choose the layer thickness.
Compaction allowance and waste are separate planning inputs. They are not a field compaction test or a substitute for the project specification.
For structural work, follow the project or agency specification for subgrade, lift thickness, moisture, drainage and relative compaction.
How the road base calculator works
Compacted road base aggregate varies by material and moisture. The calculator uses 125 lb/ft³ as a planning example; use a supplier or test value when available.
The calculator first finds the compacted base volume, applies the separate compaction allowance, then applies waste to produce an order quantity. It converts that order quantity to tons using your material density and can round the tonnage up to truck loads when you enter a legal vehicle payload.
Surface gravel and structural road base are related but not identical. Use the finished compacted thickness from the project or agency specification; the calculator does not choose structural thickness, moisture, drainage, or field compaction targets.
To estimate the material cost, enter the price per ton quoted by your local quarry or aggregate supply yard.
Roadbase calculator by square feet
If you already know the square footage of your driveway, patio, or paver walk, enter dimensions that equal that area (for example, for 1,000 square feet, use 20 ft by 50 ft). The road base calculator will convert that area into cubic yards and tons from the compacted depth you enter.
Below is a reference guide for common driveway and road base project sizes, assuming a compacted density of 125 lb/ft³, an 8% waste factor, and 0% separate compaction allowance. Replace these planning assumptions with supplier or test data.
Swipe or scroll horizontally to see more columns.
| Project size | Area | 4 in road base | 6 in road base |
|---|---|---|---|
| 20 x 20 ft driveway base | 400 sq ft | 9.00 tons | 13.50 tons |
| 800 sq ft driveway base | 800 sq ft | 18.00 tons | 27.00 tons |
| 1,000 sq ft paver base | 1,000 sq ft | 22.50 tons | 33.75 tons |
| 1,500 sq ft road base | 1,500 sq ft | 33.75 tons | 50.63 tons |
Gravel and road base cost estimate
Aggregate prices fluctuate by region but generally fall between $15 and $55 per ton at quarries. Crushed limestone is usually on the higher end, while recycled crushed concrete or crusher run gravel is more cost-efficient.
Note that our calculator estimates the cost of the raw material itself. Trucking and delivery fees often add another $50 to $150+ per load, and professional grading, compaction, and installation will increase the total project cost.
Common road base thickness requirements
Do not select a structural thickness from a generic calculator alone. Granular base and subbase thickness, lift placement, moisture, drainage, and relative compaction should follow the project or agency specification and the material supplier's requirements.
- FHWA granular base guidance: Base and subbase layers support pavement loads and help manage water; material properties and the pavement structure matter.
- Caltrans aggregate-base guidance: Follow the plans and specifications, place and compact the layer correctly, and use approved material and testing requirements.
- For a driveway or private project: Have a qualified local professional confirm thickness when soil, frost, drainage, heavy vehicles, or unusual loading is involved.
Read the FHWA granular base guidance and Caltrans aggregate-base guidance. If your supplier quotes cubic yards but you need tons, use the road base density and weight guide to understand the conversion.
FAQ
How do you calculate road base tonnage?
Multiply width by length in feet to get the area. Multiply the area by the compacted thickness in inches and divide by 324 to find the compacted cubic yards. Apply any compaction allowance first, then the separate waste factor, multiply by 27 to convert to cubic feet, multiply by the material density, and divide by 2,000 to get US tons.
What is the difference between road base, gravel base, and asphalt base?
Road base and gravel base are often used interchangeably to describe crushed rock mixed with fine stone dust (like 3/4-inch minus aggregate) that compacts into a solid layer. An asphalt base (sometimes called black base or asphalt concrete base) is a coarse asphalt hot-mix layer installed beneath the final wear surface. A driveway base is the general term for the structural foundation layer—usually made of compacted road base aggregate.
How much area does one ton of road base cover?
Using 125 lb/ft³, an 8% waste factor, and no separate compaction allowance, one US ton of road base covers approximately 44 square feet at a compacted thickness of 4 inches, or about 30 square feet at 6 inches. The real coverage changes with the supplier density and your project allowances.
Why is a road base layer required under asphalt, concrete, or pavers?
A properly specified and compacted granular base can provide load support and drainage beneath pavement. The required structure is site-specific: subgrade, water, climate, traffic, surface type, and the project specification determine the layer thickness and compaction requirements.
Can I use recycled crushed concrete as a road base?
Possibly, if the local project specification and supplier approve it. Recycled crushed concrete must meet the required gradation, cleanliness, material quality, and environmental requirements for the intended use; use the supplier's tested density rather than assuming it matches virgin aggregate.
How much does road base cost per ton?
Road base aggregate typically costs between $15 and $55 per ton, depending on your location, the type of stone (limestone, granite, or recycled crushed concrete), and delivery distance. Because gravel is very heavy, trucking costs can occasionally exceed the material cost itself.
Is roadbase the same as road base?
In many driveway and paving searches, roadbase and road base mean the same general material: compacted aggregate, gravel, crushed stone, crusher run, or class 2 base used below asphalt, concrete, pavers, or gravel surfaces. Local suppliers may use more specific product names, so match the calculator density to the material you are buying.