Gravel Calculator – Cubic Yards & Tons

How to Calculate Gravel Volume and Weight

Calculating the amount of gravel, crushed stone, or sand for your project involves two steps: determining the volume of material needed and then converting that volume to weight for ordering purposes. Gravel suppliers typically sell by the cubic yard or by the ton, so you need both figures to get an accurate quote and avoid expensive shortages or costly overages.

The volume formula is: Volume (cubic yards) = Length (ft) × Width (ft) × Depth (ft) ÷ 27. Since depth is often measured in inches, convert to feet first by dividing by 12. For example, a 20 ft × 10 ft area at 4 inches deep: 20 × 10 × (4/12) = 66.67 cubic feet ÷ 27 = 2.47 cubic yards.

To convert volume to weight, multiply the cubic yards by the material density: Weight (tons) = Cubic Yards × Density (tons per cubic yard). Standard gravel weighs approximately 1.4 tons per cubic yard, so 2.47 cubic yards × 1.4 = 3.46 tons. This calculator performs both calculations automatically — enter your dimensions, select your material type, and get instant volume and weight results.

Always add 10–15% extra material to account for compaction, spreading losses, uneven ground, and slight measurement errors. Gravel compacts 20–30% when tamped or driven over, so the installed depth will be less than the loose-fill depth unless you compensate with additional material.

Material Density Reference Table

Different aggregate materials have different densities, which directly affects how much weight you need to order for a given volume. Below is a comprehensive density reference table for common landscaping and construction aggregates:

These densities are approximate averages. Actual density varies based on moisture content (wet gravel weighs 10–20% more than dry), particle size distribution, mineral composition, and compaction level. When ordering, suppliers use a standard loose density. If you are ordering by the ton, verify with your supplier what density they use for conversions.

Recommended Gravel Depths by Application

The correct gravel depth depends on the intended use, expected traffic load, and whether the gravel serves as a base layer or a finished surface. Using too little gravel results in premature wear, exposed substrate, and poor drainage. Using too much wastes money without significant benefit.

For driveways, the industry standard is a three-layer system: 6 inches of large crushed stone base (#3 or #4, 1.5–3 inch stones), 4 inches of crusher run middle layer (compacted), and 2–3 inches of finish gravel on top (pea gravel, #57 stone, or decorative stone). Each layer should be compacted with a plate compactor or roller before adding the next layer.

Gravel Types and Best Uses

Choosing the right type of gravel is as important as calculating the right quantity. Different gravel types have different properties — some compact well for structural applications, while others are decorative and drain freely. Here is a detailed guide to the most common types:

• Pea Gravel (3/8" – 1/2"): Smooth, rounded stones available in natural earth tones. Excellent for walkways, patios, landscaping, playgrounds, and between stepping stones. Does not compact well, so it is not suitable as a structural base. Tends to migrate — use edging or borders to contain it. Cost: $25–$50 per ton.
• Crushed Stone (#57): Angular stones approximately 3/4 inch in size. The most versatile construction aggregate — used for driveways, drainage, pipe bedding, and base material. Angular shape provides good interlocking but does not compact as tightly as crusher run. Cost: $25–$45 per ton.
• Crusher Run (Dense Grade Aggregate / DGA): A blend of crushed stone and stone dust (fines) that compacts into a dense, stable surface. The best choice for driveway bases, building pad foundations, and under pavers or concrete slabs. Also called "road base" or "process." Cost: $20–$40 per ton.
• Decomposed Granite (DG): Finely crushed granite that creates a natural, packed-earth look. Popular for pathways, patios, and xeriscaping in western states. Available loose, stabilized (with a binding agent), or as a resin-coated product. Compacts moderately well. Cost: $30–$60 per ton.
• River Rock (1" – 3"): Smooth, rounded stones sourced from riverbeds. Ideal for decorative landscaping, dry creek beds, water features, and erosion control. Too large and smooth for driveways (tires spin). Available in mixed earth tones. Cost: $30–$70 per ton.
• Lava Rock: Lightweight volcanic rock available in red, black, or gray. Excellent for decorative mulch replacement, fire pit surrounds, and landscaping. Does not decompose like organic mulch. Very lightweight — a little goes a long way. Cost: $40–$80 per ton (but covers more area due to low density).
• Recycled Concrete: Crushed demolition concrete screened to size. Affordable alternative to natural crushed stone for base layers, temporary roads, and backfill. May contain rebar fragments — specify "clean" recycled concrete for residential use. Cost: $10–$25 per ton.

Building Codes and Gravel Requirements

While gravel itself is not heavily regulated, its use in construction applications is governed by building codes and engineering standards. Understanding these requirements ensures your project passes inspection and performs as intended:

• Sub-Slab Gravel (IRC R506.2.2): The International Residential Code requires a minimum 4-inch layer of clean graded gravel or crushed stone under concrete slabs on grade. The aggregate must comply with ASTM C33 and pass through a 2-inch sieve. A vapor retarder (minimum 6-mil polyethylene) must be placed over the gravel and under the concrete.
• Foundation Drainage (IRC R405): Foundations below grade require a drainage system. Drain tiles (perforated pipe) must be surrounded by at least 2 inches of washed gravel or crushed stone extending at least 6 inches beyond the drain tile. The gravel must be covered with an approved filter membrane to prevent soil intrusion.
• Septic System Gravel (state and local codes): Septic drain field trenches typically require 6–12 inches of washed gravel (#57 or similar) below and above the distribution pipe. The gravel must be free of fines (dust and small particles) to maintain proper drainage. Requirements vary by state — check with your local health department.
• Retaining Wall Drainage: Building codes and engineering standards require free-draining backfill (typically #57 crushed stone) behind retaining walls to prevent hydrostatic pressure buildup. For walls over 4 feet, a civil engineer typically specifies the drainage aggregate type and volume.
• Driveway Standards: While residential driveways are not typically code-regulated for material depth, local ordinances may require specific surface treatments for stormwater management. Some municipalities require permeable surfaces (gravel qualifies) to reduce runoff, while others require impermeable surfaces with curbing for containment.
• Playground Safety (ASTM F1292): Gravel used as playground surfacing must meet ASTM F1292 impact attenuation standards. Pea gravel in a 9-inch depth is compliant for fall heights up to 7 feet. The Consumer Product Safety Commission (CPSC) publishes specific guidelines for loose-fill playground surfacing depth requirements.
• ADA Accessibility: Gravel surfaces are generally not ADA-compliant because loose aggregate is difficult for wheelchair and mobility device users to navigate. Stabilized decomposed granite with a binding agent can meet ADA requirements for accessible paths if properly installed and maintained.
• Erosion Control: Gravel used for erosion control (riprap) on slopes or waterways must meet specific sizing and gradation requirements, often specified by the local soil and water conservation district or the Army Corps of Engineers for projects near waterways.

Ordering and Delivery Tips

How you order and receive gravel significantly impacts both cost and convenience. Here are practical tips for getting the best value:

Bulk gravel is dramatically cheaper than bagged — typically 70–80% less per ton. A single 50 lb bag covers about 0.5 cubic feet (2 sq ft at 3 inches deep), while one ton of bulk gravel covers approximately 80–100 sq ft at 3 inches deep. For any project larger than a small garden path, bulk delivery is the way to go.

When scheduling delivery, prepare the site first: clear the area where the gravel will be dumped, ensure the delivery truck has access (most require at least a 10-foot-wide path and can reach approximately 25–30 feet from the road with their dump bed), and lay down landscape fabric if using gravel over soil.

Verify the quantity upon delivery. A standard dump truck holds 10–15 tons (or 6–9 cubic yards). If you ordered a specific amount, the truck should have a weight ticket from the quarry scale showing the exact tonnage loaded. Count the loads if you ordered multiple truckloads.

Installation Best Practices

Proper installation determines whether your gravel project looks professional and lasts for years or deteriorates within months. Follow these best practices for each application type:

• Landscape Fabric: Always install commercial-grade landscape fabric (not plastic sheeting) under decorative gravel to prevent weed growth and stop the gravel from sinking into the soil. Overlap seams by 6–12 inches and pin with landscape staples every 12 inches along edges and seams.
• Edging: Install edging (steel, aluminum, plastic, or stone) around all gravel areas to prevent migration. Pea gravel and decorative stones will spread significantly without proper containment. Use 4-inch steel edging for a permanent, professional look.
• Compaction: For driveways and base layers, compact each layer with a plate compactor or hand tamper. Moisten the material lightly before compacting for best results. Crusher run should be compacted to 95% of its maximum dry density (Proctor test standard).
• Drainage: Ensure proper drainage slope — a minimum of 1% grade (1/8 inch per foot) away from structures. For driveways, crown the center 1–2 inches higher than the edges to shed water to both sides. French drains should slope at least 1% toward the discharge point.
• Layer Thickness: Spread gravel in maximum 4-inch lifts, compacting between lifts. Applying more than 4 inches of loose gravel at once results in poor compaction and uneven settlement. For a 12-inch driveway base, apply in three 4-inch lifts.

For decorative applications, the most common mistake is applying gravel too thin. A 1-inch layer looks sparse and quickly shows the landscape fabric or soil below. Apply a minimum of 2 inches (3 inches preferred) for full coverage that looks good and stays in place.