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Gravel and Base Materials Guide: Crushed Stone, Pea Gravel, and Road Base

Learn how to calculate gravel quantities for driveways, patios, and drainage projects. Compare crushed stone, pea gravel, road base, and recycled aggregates.

By HomeProjectHub Team

Gravel and base materials are the foundation of most hardscape projects. Whether you are building a gravel driveway, prepping a concrete slab, or installing a drainage system, getting the base material quantity right prevents settling, cracking, and drainage failures.

Types of Gravel and Base Materials

Crushed Stone (#57, #67, #8)

Angular stone with sharp edges that locks together under compaction. Available in sizes from 1/4 inch (#8) to 1 inch (#57). Used for driveway base layers, concrete subbase, and drainage.

Pea Gravel

Smooth, rounded stones about 3/8 inch in diameter. Used for pathways, decorative beds, and drainage. Does not lock together like crushed stone — unsuitable for driveways under vehicle traffic.

Road Base / Class 5

A mix of crushed stone and fines (stone dust) that compacts into an almost solid surface. The standard base material for roads, driveways, and parking areas under asphalt or concrete.

Recycled Concrete Aggregate (RCA)

Crushed concrete from demolished structures. Cheaper than virgin stone and performs similarly for subbase and drainage applications. May contain rebar fragments.

Calculating Gravel Volume

Volume (cu yd) = (Length × Width × Depth in ft) ÷ 27

Depth recommendations by application:

Application Recommended Depth Compaction Factor
Walkway (pea gravel) 2-3 in 1.10
Driveway (crushed stone) 4-6 in 1.15
Concrete subbase 4-8 in 1.20
Road base under asphalt 6-12 in 1.25
French drain trench 6-12 in 1.05
Paver base 4-6 in 1.15

Always multiply the calculated volume by the compaction factor. Compaction reduces volume by 10-25% depending on material type.

Weight Estimates

Gravel is often sold by weight rather than volume. Typical densities:

Material Lbs per Cubic Foot Tons per Cubic Yard
Pea gravel 95-105 1.28-1.42
Crushed stone (#57) 100-110 1.35-1.50
Road base / Class 5 110-120 1.50-1.62
Recycled concrete 100-110 1.35-1.50

Tons needed = Cubic Yards × Tons per Cubic Yard

Example Calculation

40-ft driveway, 10 ft wide, 6 inches deep, crushed stone #57

  1. Volume = 40 × 10 × (6 ÷ 12) = 200 cu ft
  2. Cubic yards = 200 ÷ 27 = 7.41 cu yd
  3. Apply compaction factor (1.15): 7.41 × 1.15 = 8.52 cu yd
  4. Convert to tons: 8.52 × 1.40 (avg) = 11.9 tons

Order 12 tons plus 1 extra ton for the driveway apron.

Common Mistakes

Skipping the compaction factor

Loose gravel settles 10-25% after compaction and vehicle traffic. If you order the exact calculated volume, you will come up short by 1-3 tons on an average driveway. Always multiply by the compaction factor.

Using pea gravel for driveways

Pea gravel looks attractive but shifts under vehicle tires, creating ruts and requiring constant raking. For driveways, use crushed stone or road base. Save pea gravel for pathways and decorative beds.

Ordering the wrong stone size

#57 stone (1 inch) provides the best balance of drainage and stability for base layers. #8 stone (1/4 inch) packs tighter but drains poorly. #3 stone (2 inches) is used for heavy drainage applications. Match the stone size to the application.

Not accounting for delivery logistics

Bulk gravel is delivered by dump truck. Ensure your driveway or drop site can accommodate a 10-15 ton truck. If not, order in smaller increments (by the scoop or bagged) at a higher per-unit cost.