Road base (also called aggregate base course, crusher run, DGA or Type 1) is a blend of crushed stone and fines that compacts into a solid, load-bearing layer under driveways, roads, slabs and pavers. Because it is compacted, you need noticeably more loose material than the finished volume – plan on 20–30% extra.
How to use the Road Base Calculator
- Material
- Custom density
- Area shape
- Length (or diameter)
- Width
- Depth
- Extra for waste and compaction
- Priced by
- Price per weight
- Price per volume
- Every result field is editable: type into Volume needed or any other result and Depth plus every other field update to match.
Results update as you type, and every field accepts the units shown in its menu.
How it works
The calculator finds the area of your rectangle, circle or triangle, multiplies it by the depth and adds the waste allowance to get the volume. Multiplying by the density of the chosen material gives the weight, and the price you enter turns either one into a cost.
Densities used
| Material | kg/m³ | lb/ft³ | US tons per yd³ |
|---|---|---|---|
| Road base (aggregate base course) | 2,243 | 140.0 | 1.89 |
| Crusher run / dense-grade aggregate | 2,100 | 131.1 | 1.77 |
| Recycled concrete road base | 1,900 | 118.6 | 1.60 |
| Asphalt millings | 1,300 | 81.2 | 1.10 |
| Type 1 MOT sub-base (UK) | 2,100 | 131.1 | 1.77 |
Good to know
A U.S. (short) ton is 2,000 lb; a metric tonne is 1,000 kg (2,204.6 lb). Quarries in the U.S. sell by the short ton, so check which one your quote uses.
Tips for an accurate estimate
- Plan driveways and paths in layers – a compacted base of larger stone does most of the structural work.
- Add 10–25% for compaction: loose stone shrinks once it is rolled or driven on.
- Ask the quarry whether prices are per US ton, metric tonne or cubic yard before comparing quotes.
- Grade surfaces at 1–2% so water runs off rather than soaking into the base.
Common mistakes to avoid
- Skipping the base layer or geotextile on soft soil, which leads to ruts and potholes.
- Using rounded stone (pea gravel, river rock) on surfaces that carry vehicles.
- Ordering compacted volume when the supplier delivers loose material.
Inputs explained
| Field | What to enter |
|---|---|
| Material | Choose one: Road base (aggregate base course), Crusher run / dense-grade aggregate, Recycled concrete road base, Asphalt millings … |
| Custom density | Units: kg/m³, lb/ft³, g/cm³, lb/yd³ |
| Area shape | Choose one: Rectangle / square, Circle (length = diameter), Triangle (length = base, width = height) |
| Length (or diameter) | Units: ft, m, in, yd, cm |
| Width | Units: ft, m, in, yd, cm |
| Depth | Units: in, cm, mm, ft, m |
| Extra for waste and compaction | In % |
| Priced by | Choose one: Weight (per ton / tonne), Volume (per yd³ / m³) |
| Price per weight | Units: /US ton, /t, /lb, /kg |
| Price per volume | Units: /yd³, /m³, /ft³ |
Formula
Volume = area × depth × (1 + waste)Weight = volume × densityCost = weight × price per ton (or volume × price per yd³)Worked example
Inputs — Material: Road base (aggregate base course); Custom density: 1,600 kg/m³; Area shape: Rectangle / square; Length (or diameter): 40 ft; Width: 12 ft; Depth: 6 in; Extra for waste and compaction: 25 %; Priced by: Weight (per ton / tonne); Price per weight: $45 /US ton; Price per volume: $60 /yd³.
Results — Area = 480 ft²; Volume needed = 11.111 yd³; Weight needed = 21.004 US ton; Estimated cost = $945.17.
Frequently asked questions
How thick should road base be?
4–6 in under patios and walkways, 6–8 in for driveways and 8–12 in or more for roads carrying trucks.
How much does road base compact?
Typically 20–30% from loose to compacted, so order extra.
How much does a yard of road base weigh?
About 3,800 lb (1.9 US tons) compacted, or around 1.4–1.6 tons loose.
What formula does the Road Base Calculator use?
Volume = area × depth × (1 + waste).