Gravel Calculator

How Gravel Volume and Weight Are Calculated

The volume formula is:

Volume (cu ft) = Length (ft) x Width (ft) x Depth (in) / 12 $$V=\frac{L\times W\times D}{12}$$

Divide by 27 for cubic yards. Multiply cubic yards by the gravel density to get weight:

$$\text{Weight (tons)}=V_{\text{yd}}\times \rho$$

Densities used: pea gravel 1.40 tons/yd3, crushed stone 1.35 tons/yd3, river rock 1.50 tons/yd3.

Variable Definitions

Length: The longest dimension of the area to be covered, in feet. For driveways, measure from the road to the garage or parking area.

Width: The shorter dimension in feet. Standard driveways are 10-12 feet wide. Two-car driveways are 20-24 feet.

Depth: The thickness of the gravel layer in inches. Deeper layers provide better coverage and last longer but cost more. 4 inches is the most common depth for residential projects.

Gravel type: Different gravel types have different densities (weight per volume). This affects how many tons you need to order. Heavier gravel costs more per ton but may require less volume.

Worked Example

A garden path: 30 ft long, 3 ft wide, 3 inches deep with pea gravel.

1. Volume in cubic feet: 30 x 3 x (3/12) = 22.5 cu ft
2. Cubic yards: 22.5 / 27 = 0.833 cu yd
3. Cubic meters: 22.5 / 35.315 = 0.637 cu m
4. Weight: 0.833 x 1.40 = 1.167 tons (1,059 kg)

Edge Cases and Advanced Scenarios

Compaction factor: Gravel compacts 10-15% when driven over or tamped. If you need a finished depth of 4 inches, apply 4.5-5 inches initially. Crushed stone compacts more than rounded pea gravel because the angular edges interlock.

Drainage applications: French drains and dry wells need 12+ inches of gravel depth. Use washed gravel (no fines) for drainage to prevent clogging. Standard gravel with dust fines packs tighter but drains slower.

What to Do with Your Result

• Call 2-3 local gravel suppliers with your cubic yard and tonnage numbers to compare prices per ton delivered.
• Ask about delivery minimums. Most suppliers require a 5-ton minimum for dump truck delivery.
• Prepare the area before delivery: remove vegetation, grade the surface, and lay landscape fabric.
• Rent a plate compactor for driveways and high-traffic areas to lock the gravel in place.