How Much Road Base for a 12x35 Driveway?
How much road base for a 12x35 driveway is a quick volume problem. 420 square feet at 4 inches comes to 5.19 cubic yards. Road base usually weighs about 1.4 to 1.65 compacted tons per cubic yard, so plan on roughly 7.8 tons.
Volume and tonnage calculator →The math for a 12x35 driveway
- Area: 12 × 35 = 420 sq ft.
- Depth in feet: 4 ÷ 12 = 0.333 ft.
- Cubic feet: 420 × 0.333 = 140.0 cu ft.
- Cubic yards: ÷ 27 = 5.19 yd³.
- Tons: × 1.5 = 7.8 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 | 5.19 | 7.8 | 8.6 |
| 6 in | 7.78 | 11.7 | 12.8 |
| 8 in | 10.37 | 15.6 | 17.1 |
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. Ask your supplier for their own tons-per-yard figure, since stone source and moisture shift it.
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. This driveway sees car and truck traffic, so match the depth to that load rather than to the minimum.
Ordering tips
- Round up. Compaction and uneven ground eat material. Adding about 10 percent is common.
- Delivery size. 8.6 tons fits in a single 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.
Good and poor uses for road base
Best suited to:
- 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 8x16 area at 2 inches takes about 1.2 tons.
- Weight used here: about 1.5 tons per cubic yard.
Mistakes that throw off the order
- Mixing up cubic yards and tons. Yards are volume, tons are weight; convert with the product’s weight per yard.
- Using inches as if they were feet. Depth has to be divided by 12 before you multiply; skipping that step inflates the order twelvefold.
- Ignoring the base. A thin surface layer over soft soil fails early no matter how much material is on top.
- Skipping drainage. Water sitting under any surface softens the base and leads to ruts and potholes.
Questions people ask
How many tons of road base for a 12x35 driveway?
About 7.8 tons at 4 inches deep, or 8.6 tons with 10 percent extra.
How many cubic yards is a 12x35 driveway at 4 inches?
About 5.19 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 12x35?
420 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 12x25 Driveway?
- How Much Road Base for a 12x30 Driveway?
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