Road Base Calculator
Calculate the tons of road base needed under driveways, pads and paths.
What you'll need to order
- crusher run / road base
- geotextile fabric
- compaction plate rental
Prices vary by region and haul distance. Get quotes from at least two local suppliers.
How this calculator works
tons = length × width × (depth ÷ 12) × 135 ÷ 2000
Compacted road base weighs about 135 lb per cubic foot, roughly 3,645 lb per cubic yard — noticeably denser than clean stone because the fines fill the voids. This figure is for the compacted depth you want to end up with.
Switch the site to metric — the control is in the footer — and your inputs, your results and the tables below follow. The formula, the constants, the guidance text and the sources stay in US units on purpose: that is how the standards they come from are written, and restating them would detach each figure from the document you are meant to be able to check it against.
Where these numbers come from
- ASTM C29/C29M 2023 — the test method that defines bulk density for road base; the figure used here is a typical published value, not a mandated one
- AASHTO T 180 (Moisture-Density Relations of Soils) 2020 — the compacted density road base is placed and paid for at
Check the edition. Codes are amended every few years, and the one your inspector works from may not be the one named above.
Worked example
With length 10 ft, width 10 ft, compacted depth 4 in, this calculator returns 2.25 tons.
Road base for common drives and pads
Every row here opens the calculator already filled in. Copy that link and the numbers travel with it.
| Job | Size | Road base needed |
|---|---|---|
| Shed pad | 12 ft × 10 ft × 4 in | 2.70 tons |
| Single-car drive | 40 ft × 10 ft × 6 in | 13.50 tons |
| Two-car drive | 40 ft × 20 ft × 6 in | 27.00 tons |
| Long rural drive | 300 ft × 12 ft × 8 in | 162.0 tons |
| Equipment parking pad | 30 ft × 30 ft × 8 in | 40.50 tons |
This is compacted depth. Order about 25% more loose material than the compacted figure suggests.
Frequently asked questions
How much road base do I need for a driveway?
A 40 by 12 ft driveway at 6 inches compacted depth needs about 16 tons. Multiply area by depth in feet, multiply by 135, then divide by 2,000.
How thick should road base be under a driveway?
Four to six inches for cars on firm soil, 8 to 12 inches where trucks park or the subgrade is clay. Soft ground needs geotextile fabric underneath as well, or the base will pump down into the soil.
What is the difference between road base and crushed stone?
Road base, also sold as crusher run or dense-grade aggregate, contains stone dust and fines that let it lock together and compact hard. Clean crushed stone has the fines washed out — it drains better but stays loose and cannot form a structural base.
How many lifts should road base go down in?
Compact in layers of 4 inches or less. A 6 inch base means two passes, an 8 inch base means two, and 12 inches means three. Dumping the full depth and compacting once leaves the bottom loose, which is the most common cause of driveway failure.
How much does a yard of road base weigh?
About 3,600 lb, or 1.8 tons, compacted. That is heavier than most aggregates, so a tandem dump truck legally carries around 8 cubic yards rather than the usual 10 to 14.