How Much Road Base for a 18x120 Driveway?
A 18 by 120 foot driveway is 2,160 square feet. How much road base for a 18x120 driveway depends on depth: at 4 inches it is about 26.67 cubic yards or 40.0 tons. Suppliers usually sell by the ton, so the tonnage is the number to give them.
Volume and tonnage calculator →The math for a 18x120 driveway
- Area: 18 × 120 = 2,160 sq ft.
- Depth in feet: 4 ÷ 12 = 0.333 ft.
- Cubic feet: 2,160 × 0.333 = 720.0 cu ft.
- Cubic yards: ÷ 27 = 26.67 yd³.
- Tons: × 1.5 = 40.0 tons.
The volume and tonnage calculator does this for any size.
Road base needed by depth
| Depth | Cubic yards | Tons (approx.) | Tons +10% |
|---|---|---|---|
| 4 in | 26.67 | 40.0 | 44.0 |
| 6 in | 40.00 | 60.0 | 66.0 |
| 8 in | 53.33 | 80.0 | 88.0 |
About road base
Road base (also called base rock, ABC, or Class 2 base in different states) is a graded mix of stone and fines made to compact into a load-bearing layer. If the yard sells by the cubic yard instead of the ton, use the cubic-yard column directly.
Preparing the driveway
Strip sod and soft topsoil, grade for drainage and compact the subgrade before any stone goes down. Gravel drives last longer with a compacted base layer under the top stone and a slight crown so water runs off. For car and truck traffic, the depths in the table above are a reasonable starting range.
Ordering tips
- Round up. Compaction and uneven ground eat material. Adding about 10 percent is common.
- Delivery size. 44.0 tons may take more than one typical dump truck load; small loads may carry a delivery fee. See how many tons of gravel in a dump truck.
- Bulk vs bags. At this size bulk delivery is usually the practical choice.
- Where it drops. Have the truck dump as close to the driveway as firm ground allows.
Where road base fits
Works well for:
- Base under asphalt and concrete
- Gravel roads and drives
- Equipment and shed pads
Less suited to:
- Drainage layers
- Decorative surfaces
- Surfaces that will stay uncompacted
Quick reference numbers
- Per inch over 100 sq ft: about 0.46 tons of road base (0.31 cubic yards).
- Per inch over 1,000 sq ft: about 4.6 tons.
- Another size for comparison: a 10x20 area at 4 inches takes about 3.7 tons.
- Weight used here: about 1.5 tons per cubic yard.
Where estimates go wrong
- Ignoring the base. A thin surface layer over soft soil fails early no matter how much material is on top.
- Using inches as if they were feet. Depth has to be divided by 12 before you multiply; skipping that step inflates the order twelvefold.
- Forgetting that compaction shrinks loose material. A loose 4-inch spread of a dense-graded stone may finish closer to 3 inches after rolling.
- Mixing up cubic yards and tons. Yards are volume, tons are weight; convert with the product’s weight per yard.
Questions people ask
How many tons of road base for a 18x120 driveway?
About 40.0 tons at 4 inches deep, or 44.0 tons with 10 percent extra.
How many cubic yards is a 18x120 driveway at 4 inches?
About 26.67 cubic yards.
How much does a cubic yard of road base weigh?
Usually around 1.4 to 1.65 compacted tons, depending on stone size, fines and moisture.
How deep should road base be for a driveway?
The table above shows 4 to 8 inches. Shallower depths suit top dressing; deeper depths suit new installs and heavier use.
How many square feet is 18x120?
2,160 square feet.
Related guides
- Crushed Stone vs Gravel: Differences and Best Uses
- Tons to Cubic Yards for Gravel: Conversion Chart
- How Many Tons of Gravel in a Dump Truck? Loads and Coverage
- How Much Does a Ton of Gravel Cover? Depth Chart
- How Much Road Base for a 18x90 Driveway?
- How Much Road Base for a 18x100 Driveway?
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