Base rock for driveways and pads · tons, yards, compaction
Road base calculator
Enter length, width and depth to calculate road base in cubic yards and US tons. The preset is a published weight of 2,860 lb per cubic yard, loose. For a compacted depth, add about 25%, the allowance implied by WSDOT’s loose and compacted weights.
How much road base you need
Enter your dimensions to see cubic yards, tons and bags
Enter your dimensions to see cubic yards, weight and bags, with every assumption explained.
The short answer
How much road base do I need?
Multiply length × width in feet by depth in inches, then divide by 324 for cubic yards. A 12 × 40 ft driveway base at 4 in needs 160 ft³, or 5.93 cubic yards, which is about 8.47 US tons at the Sutherland Landscape Supplies figure of 2,860 lb per cubic yard (1.43 tons per yard). Enter your finished depth, then set the extra allowance to about 25% under Material & allowance if that depth is compacted.
The calculation
How to calculate road base in four steps
- Measure the area.Length × width in feet gives square feet. Split an L-shape into rectangles and add each as a separate area above.
- Convert the depth.Divide depth in inches by 12. Three inches is 0.25 ft; four inches is 0.333 ft.
- Find the volume.Square feet × depth in feet gives cubic feet. Divide by 27 for cubic yards. Volume does not depend on the material.
- Convert to tons.Multiply cubic yards by the supplier’s pounds per cubic yard and divide by 2,000. At 2,860 lb/yd³ that is 1.43 tons per yard.
Rectangle · US measurements
Length × Width × Depth ÷ 324
Feet × feet × inches → cubic yards
Cubic yards × 2,860 ÷ 2,000
Cubic yards × lb/yd³ → US tons at the reference weight
Read the full calculation method ↗Worked examples
Road base calculator examples
Each example uses the 105.93 lb/ft³ reference, no extra allowance and no compaction adjustment. Open one to load its measurements into the calculator, then change the depth or density to match your product.
| Project | Volume | Weight |
|---|---|---|
| 12 × 40 ft driveway base at 4 in | 160 ft³ · 5.93 yd³ | 8.47 US tons |
| 20 × 20 ft parking pad at 6 in | 200 ft³ · 7.41 yd³ | 10.59 US tons |
| 10 × 12 ft shed pad at 4 in | 40 ft³ · 1.48 yd³ | 2.12 US tons |
Suppliers sell by the ton or by the cubic yard. Ask which unit the quote uses and which weight per yard they bill by; the calculator’s Bag sizes & cost section accepts either.
Bulk quantities
How much does a ton or a cubic yard of road base cover?
One cubic yard is 27 ft³ whatever the material. One US ton of this reference product is 18.88 ft³ (0.7 yd³), so its coverage depends on the published weight.
Coverage by depth
| Depth | One cubic yard covers | One US ton covers |
|---|---|---|
| 3 in | 108 ft² | 75.52 ft² |
| 4 in | 81 ft² | 56.64 ft² |
| 6 in | 54 ft² | 37.76 ft² |
| 8 in | 40.5 ft² | 28.32 ft² |
Material for 100 square feet
| Depth | Cubic yards | US tons |
|---|---|---|
| 3 in | 0.93 yd³ | 1.32 tons |
| 4 in | 1.23 yd³ | 1.77 tons |
| 6 in | 1.85 yd³ | 2.65 tons |
| 8 in | 2.47 yd³ | 3.53 tons |
Multiply the 100 ft² row by your area ÷ 100. The ton-of-gravel coverage guide explains the arithmetic, and the cubic yards to tons converter compares several published weights side by side.
Why the density matters
Published weights for road base
A size or grade label does not fix a density. These are the published figures behind this page; each names the supplier and product it describes, and none is a specification for another yard’s material.
| Product | Supplier | lb per yd³ | Tons per yd³ | 10 yd³ weighs |
|---|---|---|---|---|
| Road Base | Sutherland Landscape Supplies | 2,860 | 1.43 | 14.3 tons |
| Virgin Class 2 Base Rock | Lyngso Garden Materials | 3,000 | 1.5 | 15 tons |
| Recycled Road Base, 1.5 inch minus | Rock N Yard | 2,600 | 1.3 | 13 tons |
| Crushed Surfacing Base Course, truck measure | Washington State DOT | 2,950 | 1.48 | 14.75 tons |
Enter your own supplier’s figure under Material & allowance to replace the preset. The full gravel density reference records every figure with its source and date.
Loose versus compacted
Road base compaction: how much loose material to order
Washington State DOT’s design manual lists crushed surfacing base course at 2,950 lb per cubic yard loose (truck measure) and 3,700 lb compacted, both dry. The same tonnage therefore occupies 1.25 times as much space on the truck as in the finished layer.
| Compacted depth | Loose depth to spread | Loose yd³ per 100 ft² |
|---|---|---|
| 3 in | 3.76 in | 1.16 yd³ |
| 4 in | 5.02 in | 1.55 yd³ |
| 6 in | 7.53 in | 2.32 yd³ |
| 8 in | 10.03 in | 3.1 yd³ |
This is one agency’s figure for one specification, applied as arithmetic. Moisture, grading and compaction effort change the result; follow your supplier or engineer where they differ. For a complete driveway with separate base and top layers, use the gravel driveway calculator; for a patio, the paver base calculator.
Before you order
Frequently asked questions about road base
Every answer states the weight per yard it assumes.
Check our formulas & sources ↗How much road base do I need?
Multiply length × width in feet by depth in inches and divide by 324 for cubic yards. A 12 × 40 ft driveway base at 4 in is 5.93 cubic yards, about 8.47 US tons at 2,860 lb per yard. To finish at 4 inches compacted, WSDOT’s loose and compacted weights imply ordering about 7.43 loose yards (10.63 tons).
How many tons of road base per cubic yard?
Published loose figures on this page run from 2,600 lb (1.3 tons) to 3,000 lb (1.5 tons) per cubic yard. Recycled road base is at the light end. WSDOT lists crushed surfacing base course at 2,950 lb loose and 3,700 lb compacted, dry.
How much extra road base do I need for compaction?
Using WSDOT’s published dry weights, a compacted cubic yard holds 3,700 ÷ 2,950 = 1.25 loose yards, so order about 25.42% more than the compacted volume. Put another way, the layer loses about 20.27% of its loose volume. Your supplier’s figure for its own product takes priority.
How much road base do I need for 100 square feet?
At 4 inches, 100 ft² needs 1.23 cubic yards (1.77 tons) measured as a loose volume; at 6 inches 1.85 yd³ (2.65 tons). Add the compaction allowance if those are compacted depths.
How much does a ton of road base cover?
At 2,860 lb per cubic yard, one US ton is 18.88 ft³ loose. It covers about 75.52 ft² at 3 inches, 56.64 ft² at 4 inches or 37.76 ft² at 6 inches, before compaction.
Is road base the same as crusher run?
They are close relatives: both are crushed stone with fines that compact into a firm layer, and the names vary by region (road base, base rock, Class 2, ABC, crusher run, CA6). Check the local grading. The crusher run calculator uses a published crusher run weight.
How deep should road base be?
Use the depth in your plan or specification. The examples here show the arithmetic only. Base depth depends on the subgrade, drainage and the loads it carries, which a quantity calculator cannot judge.
How is the parking pad example calculated?
A 20 × 20 ft pad is 400 ft². 400 × (6 ÷ 12) = 200 ft³, or 7.41 cubic yards, which weighs 10.59 US tons at 2,860 lb per yard. As a compacted depth, order about 9.29 loose yards.
References
- Road Base: 2,860 lb/yd³, Sutherland Landscape Supplies. Recorded September 23, 2026
- Virgin Class 2 Base Rock: 1.5 US tons/yd³, Lyngso Garden Materials. Recorded September 23, 2026
- Recycled Road Base, 1.5 inch minus: 1.3 US tons/yd³, Rock N Yard. Recorded September 23, 2026
- Crushed Surfacing Base Course, truck measure: 2,950 lb/yd³, Washington State DOT. Recorded September 23, 2026
About these calculations
By Site Measure · Last updated . The 2,860 lb per cubic yard reference is Sutherland Landscape Supplies’ published weight for its own road base. The compaction ratio comes from WSDOT Design Manual Exhibit 620-1. The examples are illustrative arithmetic, not measured deliveries, product specifications or installation depths. Content was prepared with AI assistance and checked against the calculator’s arithmetic tests; no independent engineering review is claimed.
See our calculation checks or report a calculation discrepancy with your dimensions, density and units.