Road Base Calculator
Estimate road-base aggregate in cubic yards and short tons. The compacted layer dimensions drive both quantities for a chosen aggregate density.
How the result changes
Only base length changes; all other inputs stay at your current values. The line illustrates the formula across the shown range. This is not a forecast of real-world outcomes.
About this calculation
Road base is specified as a compacted layer, but bulk aggregate may be sold by yard or ton. This tool translates the planned layer geometry into both measures using a density selected for the actual aggregate blend. Calculate road base when building or resurfacing a driveway.
Formula
compacted cubic yards = length × width × (depth/12) ÷ 27
Worked example
With Base length: 30 ft, Base width: 10 ft, Compacted depth: 6 in, Compacted density: 130 lb/ft³, compacted volume is 5.555556 yd³.
Inputs and units
Measure the base footprint in feet and specify the compacted depth in inches. The density should be the mass per finished cubic foot of the intended crushed aggregate, since a loose truckload and compacted pavement bed occupy different volumes.
- Base length (ft): Measure the finished road-base run along the centerline of the section.
- Base width (ft): Include the entire compacted base width, which may extend beyond paving.
- Compacted depth (in): Use the specified compacted thickness in inches.
- Compacted density (lb/ft³): Replace this sample density with the supplier's value for the aggregate blend.
Calculation and worked example
Multiply length by width for square feet, and divide the inch depth by 12 to convert it to feet. Their product is compacted cubic feet. Divide by 27 for cubic yards, or multiply by pounds per cubic foot and divide by 2,000 for short tons In compact notation, compacted cubic yards = length × width × (depth/12) ÷ 27.
A 30 ft by 10 ft base at 6 in compacted depth occupies 150 ft³, which is about 5.556 yd³. At an assumed 130 lb/ft³, its estimated mass is 19,500 lb, or 9.75 US short tons.
How to use the answer
These figures describe the finished layer before adjusting for delivered loose volume. The supplier may quote truckloads by loose cubic yard or invoice by weight; ask how the quoted unit maps to the compacted quantity required on site.
Calculate sections with different widths or thicknesses independently, then total the short tons. That is useful for a widened turn area attached to a narrower driveway or a base course with local reinforcement.
Assumptions and checks
The footprint is rectangular and the compacted depth uniform. The calculator has no built-in swell or compaction factor because that depends on gradation, moisture, and how material is placed; add it only using a verified project value.
Do not multiply by 6 as if inches were feet, and do not compare metric tonnes directly with US short tons. A density from an unrelated aggregate can be a larger error than rounding the final volume.
For a 12 in base, cubic feet equal footprint square feet. A 6 in base should therefore use half as many cubic feet; use that relationship to check an estimate before ordering.
Common questions
What does the compacted volume result represent?
It is the geometric compacted layer volume in cubic yards. The second result applies your bulk density to estimate US short tons.
What should I check before relying on this result?
Verify the compacted thickness, base width, and aggregate density. Confirm whether the seller's quoted yards describe loose or compacted material.
Inputs
- Base length (ft)
- Base width (ft)
- Compacted depth (in)
- Compacted density (lb/ft³)