Road base — also called crusher run, base course or aggregate base — is a mix of crushed stone and fines that compacts into a firm layer under driveways, pavers and slabs. Enter the area and compacted depth to estimate how much to order.
Road base compacts by around 10–20%, so order for the depth you want after compaction and keep some extra in the waste allowance.
Formula
Tons = Area × Depth × Density
The default density of 2,800 lb/yd³ (about 1.66 t/m³) is a typical loose value; ask your supplier for theirs.
Worked example
A 12 ft × 10 ft area at 4 inches: 40 ft³ = 1.48 yd³ ≈ 2.07 tons of road base, or about 2.18 tons with 5% extra.
Frequently asked questions
How thick should road base be?
Commonly 4 inches (10 cm) under patios and walkways and 6–8 inches (15–20 cm) under driveways, compacted in layers.
What is the difference between road base and gravel?
Road base contains fine particles that bind when compacted, making a solid layer. Clean gravel has no fines, so it drains well but does not lock together.
Last updated · Calculations checked by automated tests· Editorial policy