How do I calculate road base volume?

Multiply the length by the width by the depth (all in feet) to get cubic feet, then divide by 27 to convert to cubic yards. The formula is: Volume (yd³) = (Length × Width × Depth in ft) ÷ 27.

How many tons of gravel do I need for a driveway?

Multiply the volume in cubic yards by the material density. For dry loose gravel (density ~1.28 tons/yd³), a 10 ft × 60 ft driveway at 4 inch depth needs about 7.4 cubic yards, or roughly 9.5 tons.

What depth of road base do I need?

For a light residential driveway, 4 to 6 inches is typical. For a road or parking lot with heavier traffic, 6 to 12 inches or more is common. Always follow your local engineering specification.

Should I add extra material for compaction?

Yes. Add 5 to 15 percent extra to account for compaction and waste so you do not run short after rolling. Enter a compaction percentage in the calculator to get an adjusted quantity.

What is the best material for a road base?

Crushed limestone or crushed stone is the most common choice because it locks together well and stays stable. Gravel works for light-use driveways where drainage is important. Recycled asphalt pavement (RAP) is a budget-friendly and eco-friendly option.

Road Base Calculator | Volume, Weight & Cost Estimator

Road Base Calculator

Estimate volume, weight and cost for driveways, roads and parking lots instantly.

Length

Width

Depth

Material

Custom Density (kg/m³)

Adjustments optional

Compaction Extra (%)

Waste & Overrun (%)

Cost Estimate optional

Price

Price Per

Results

Measurement	Value

Road Base Material Densities

Road base material density values are used to convert volume to weight. These figures are accepted industry estimates for planning and budgeting.

Material	kg/m³	lb/yd³	tons/yd³ (approx)
Gravel, dry, loose	1522	2565	1.28
Gravel, natural with sand	1922	3240	1.62
Gravel, dry 1/4 to 2 inch	1682	2835	1.42
Limestone, broken	1554	2619	1.31
Limestone, pulverized	1394	2350	1.17
Asphalt (2200 kg/m³)	2200	3707	1.85
Asphalt (2300 kg/m³)	2300	3876	1.94
Clay, dry	1089	1836	0.92
Clay, wet	1826	3078	1.54
Clay, compacted	1746	2943	1.47
Dirt, dry loam	1249	2105	1.05
Dirt, moist	1442	2431	1.21
Sand, dry / Dirt, wet	1602	2700	1.35
Granite, broken	1650	2781	1.39
Sand with gravel, wet	2020	3405	1.70

How to Calculate Road Base Volume

Road base volume calculation follows a simple three-step process. You need three measurements: the length, width, and depth of your base layer.

Convert all measurements to feet. (Depth in inches: divide by 12. Width/Length in yards: multiply by 3.)
Multiply Length × Width × Depth (in feet) to get cubic feet.
Divide cubic feet by 27 to get cubic yards.
Multiply cubic yards by the material density in tons per cubic yard to get weight in tons.
Add your compaction and waste percentage to get the final order quantity.

Worked Example: Driveway Base

Driveway: 60 ft long, 10 ft wide, 6 inch deep gravel base.
Depth in feet: 6 ÷ 12 = 0.5 ft
Volume: 60 × 10 × 0.5 = 300 ft³
Cubic yards: 300 ÷ 27 = 11.11 yd³
Weight (dry gravel, 1.28 tons/yd³): 11.11 × 1.28 = 14.22 tons
With 10% compaction extra: 14.22 × 1.10 = 15.64 tons to order

Calculating Irregular Areas

Calculating an irregular area is straightforward when you split it into rectangles. Measure each rectangular section separately, calculate the volume of each, then add the totals together. If you already know the total area in square feet, just enter that times the depth directly.

Choosing the Right Road Base Material

Choosing the right road base material depends on your load requirements, drainage needs and budget.

Material	Best For	Key Benefit	Drawback
Crushed limestone / crushed stone	Roads, parking pads, heavy driveways	Locks together tightly, very stable	Can be dusty, slightly higher cost
Gravel	Light driveways, rural roads	Excellent drainage, budget-friendly	Can shift and rut under heavy loads
Recycled asphalt (RAP)	Cost-saving and eco projects	Low cost, compacts well, reduces waste	Quality varies, availability limited
Asphalt surface course	Top layer only	Smooth, sheds water, quiet	Needs hot installation, not a base by itself

Key Road Base Terms Explained

Key road base terms help you communicate clearly with suppliers and engineers.

Subgrade

The natural ground beneath the road. Preparing and compacting the subgrade ensures it can support all the layers above without settling.

Base Course

The crushed rock or aggregate layer that sits directly on the subgrade. It spreads the load from the surface down to the ground.

Compaction

The process of rolling or tamping the base layer so that air voids collapse and particles interlock. Proper compaction is what makes a base strong and durable.

Optimum Moisture Content (OMC)

The moisture level at which a material compacts to its greatest density. Material that is too dry or too wet will not compact properly and will perform poorly.

Crown (Cross-Slope)

A slight downward slope of about 2 percent built across the road surface. The crown sheds rainwater to the side so the base layer stays dry and lasts longer.

Frequently Asked Questions

Multiply the length by the width by the depth (all converted to feet) to get cubic feet. Divide by 27 to get cubic yards. The formula is: Volume (yd³) = (Length × Width × Depth in feet) ÷ 27. Use the calculator above to do this automatically.

Multiply your volume in cubic yards by the gravel density. For dry loose gravel at roughly 1.28 tons per cubic yard, a 10 ft by 60 ft driveway with a 4 inch base requires about 7.4 cubic yards, or approximately 9.5 tons before adding extra for compaction and waste.

For a light residential driveway, 4 to 6 inches is a typical starting point. For a road or parking lot with heavier vehicle traffic, 6 to 12 inches or more is standard. Always follow your local engineering specification or ask your materials supplier.

Yes. Ordering 5 to 15 percent more than your calculated volume is standard practice. Compaction reduces the thickness of the loose material, and some waste always occurs during spreading. The calculator’s Compaction and Waste fields handle this adjustment for you.

Crushed limestone or crushed stone is the most widely recommended road base material. It interlocks well when compacted and creates a very stable surface. Gravel is a good option for light driveways where drainage matters most. Recycled asphalt pavement (RAP) is a cost-effective eco-friendly alternative.

Yes. Enter the total length and width of the parking lot area (or break it into sections), choose your base material, and set the required depth. The calculator returns total volume, weight, and estimated cost just as it does for a road or driveway.

The sub-base is a lower layer of coarser aggregate placed directly on the subgrade (native soil). The base course sits on top of the sub-base and is made of finer, well-graded material that provides the main load-bearing support. The surface layer (asphalt or concrete) goes on top of the base.