Gravel Calculator

How the Gravel Calculator Works

The gravel calculator estimates the volume and weight of gravel needed for any project. Volume formula: Cubic feet = Length (ft) × Width (ft) × Depth (ft). Convert to cubic yards by dividing by 27. Convert to tons by multiplying cubic yards by the gravel's density (typically 1.35–1.7 tons per cubic yard depending on type).

Example: A driveway 60 ft long × 12 ft wide with 4 inches (0.33 ft) depth: Volume = 60 × 12 × 0.33 = 237.6 cubic feet ÷ 27 = 8.8 cubic yards. At 1.4 tons/yard: 8.8 × 1.4 = 12.3 tons. Expect to pay $200–$600 for that load depending on gravel type and your region, plus delivery and spreading costs.

How Much Gravel Do I Need? Depth Guidelines by Project Type

Recommended gravel depths vary by application:

• Driveway (top layer): 3–4 inches of gravel; if installing new, use 6–8 inches total with compacted base layers.
• Walkways and paths: 2–3 inches is sufficient; 1.5 inches minimum to prevent weed breakthrough.
• Drainage trenches: Fill completely; typically 6–12 inches deep.
• Landscaping beds: 2–3 inches for decorative coverage; prevents weeds and retains moisture when used over landscape fabric.
• Under concrete slabs: 4–6 inches of compacted gravel base is required for stability and drainage.
• French drain: 6–12 inches of washed stone around perforated pipe; key is drainage — use 3/4-inch clean gravel, not pea gravel.
• Pea gravel patio: 3–4 inches for a stable surface that stays in place; add edging to prevent migration.

Gravel Weight Calculator: Tons vs. Cubic Yards

Gravel is sold by weight (tons) or volume (cubic yards) depending on supplier. Conversion densities by gravel type:

• Crushed stone (limestone, granite): ~1.4–1.5 tons per cubic yard
• Pea gravel: ~1.3–1.4 tons per cubic yard (rounder = less dense packing)
• River rock / decorative rock: ~1.2–1.35 tons per cubic yard
• Lava rock: ~0.5–0.7 tons per cubic yard (very lightweight)
• Decomposed granite: ~1.4–1.6 tons per cubic yard
• Gravel base (road base / crusher run): ~1.5–1.75 tons per cubic yard (dense-graded aggregate)

Rule of thumb: 1 cubic yard of standard gravel weighs approximately 2,700–3,000 pounds (1.35–1.5 tons). A full pickup truck bed holds about 0.5 cubic yards (~800–900 lbs); a standard dump truck delivers 10–14 cubic yards per load.

Pea Gravel Calculator: Coverage and Cost

Pea gravel (1/4 to ⅜ inch smooth stones) is one of the most popular landscaping materials. Coverage: one ton of pea gravel covers approximately:

• 100 sq ft at 2-inch depth
• 75 sq ft at 3-inch depth (recommended minimum)
• 50 sq ft at 4-inch depth

Pea gravel pricing as of 2025: $35–$70 per ton from a local quarry (bulk); $4–$6 per 50-lb bag from home improvement stores (about $160–$240/ton equivalent — much more expensive for small projects). Delivery typically adds $50–$150 depending on distance. Plan on 5–10% overage for irregular shapes and settling.

Driveway Gravel Calculator: Full Installation Guide

A properly constructed gravel driveway uses multiple layers for stability and longevity:

• Base layer (bottom, 4 in): Large aggregate (2–3 inch stones) for structural support. This layer is compacted.
• Middle layer (3–4 in): Medium aggregate (1–2 inch) for drainage and stability.
• Top layer (2–3 in): Fine gravel (3/4-inch crushed stone or pea gravel) for drivable surface.

Total depth: 9–11 inches of gravel. For an average 2-car driveway (20 ft × 40 ft = 800 sq ft): Base layer: 800 × (4/12) ÷ 27 = 9.9 cubic yards. Middle: 7.4 cubic yards. Top: 4.9 cubic yards. Total: ~22 cubic yards = ~30 tons of gravel. At $25–$40/ton plus delivery and grading: budget $1,200–$2,500 for materials on a standard installation.

Frequently Asked Questions

How many bags of gravel equal a cubic yard?

Standard gravel bags are 50 lbs. At ~2,800 lbs/cubic yard: you need about 56 bags per cubic yard. At $5–$6/bag, that's $280–$336 per cubic yard from bags vs. $25–$40/yard in bulk — about 8–10× more expensive. Bags make sense for small accent areas under 0.5 cubic yards; bulk delivery is always more economical for larger projects.

Does gravel need to be replaced over time?

Gravel driveways and paths need periodic top-dressing every 3–5 years as stones compact, scatter, and wash away. Top dress with 1–2 inches of fresh gravel to restore surface level. Driveways with proper edging and slight crown (higher in center) shed water and retain gravel much better. Weed fabric under the gravel significantly extends the time between major refurbishments.