Decomposed Granite Calculator: Volume, Weight & Cost Estimator

A decomposed granite calculator converts your project dimensions into the exact loose volume and quarry tonnage needed for delivery. Whether you are building a modern landscape walkway, patio, or driveway, factoring in the critical 20% to 25% compaction rate prevents expensive mid-project shortages, sunken edges, and uneven settlement.

Calculate Decomposed Granite Volume, Tonnage & Delivered Cost

Use the calculation engine below to generate your complete material takeoff. Choose your project layout, enter the dimensions, select your aggregate grade, and input your project pricing to calculate required volume, in-place compaction tonnage, and estimated costs.

How Do You Calculate Decomposed Granite? The 324 Constant & Compaction Rule

To calculate decomposed granite requirements, multiply the surface length by width in feet to get square footage, multiply by the intended depth in inches, divide by 324 to determine loose cubic yards, and multiply by 1.25 to account for the mandatory 20% to 25% compaction shrinkage under mechanical tamping.

A standard cubic yard equals 27 cubic feet. Because depth is measured in inches while length and width are measured in feet, dividing 27 cubic feet by 12 inches yields the mathematical constant of 324. One cubic yard of material spread across 324 square feet will produce a layer exactly 1 inch deep before compaction.

Four Steps to Calculate Your Material Takeoff:

1. Calculate Surface Area: Measure the perimeter length and width in linear feet. Multiply length by width to obtain total square footage. For irregular or curved perimeters, calculate the average width across 5-foot intervals.
2. Convert Area and Depth to Loose Volume: Multiply your total square footage by the planned installation depth in inches, then divide by 324. This number represents your uncompacted, loose volume in cubic yards.
3. Factor Vibratory Compaction Swell: Decomposed granite consists of 3/8-inch granite particles down to fine stone dust. When packed with a vibratory plate compactor, smaller fines migrate into the open voids between larger grains. Multiply your loose cubic yards by 1.25 to compensate for this 25% volume loss. Ordering without this multiplier results in a finished depth that falls 1/2 to 3/4 inch below your edging borders.
4. Convert Cubic Yards to Billing Tonnage: Commercial aggregate quarries sell DG by the short ton (2,000 pounds), not by the cubic yard. Multiply your adjusted cubic yards by your chosen material’s density rating (1.35 for natural DG; 1.45 to 1.60 for stabilized mixes) to determine exact delivery weight.

What Depth of Decomposed Granite Is Required for Walkways, Patios, and Driveways?

Decomposed granite requires a finished compacted depth of 2 inches for pedestrian garden pathways, 3 inches for outdoor patios and fire pit surrounds, and 4 to 6 inches installed over a compacted crushed aggregate base course for vehicular driveways.

Applying DG thicker than 2 inches in a single loose pass causes a structural failure known as bridging. When a heavy vibratory plate compactor passes over a 4-inch loose lift, the top 1.5 inches consolidate into a rigid crust, but the downward vibrational energy dissipates before reaching the bottom layer. The trapped, uncompacted lower material remains loose, causing the surface to yield, form ruts, and turn spongy under winter rains.

To achieve a true 3-inch finished patio, spread your material in two separate 1.9-inch loose lifts. Moisture-condition each layer with a fine hose mist, then run an 80-pound or heavier plate compactor over the surface three times per lift before spreading the next course.

How Does Decomposed Granite Type Affect Weight and Tonnage?

Decomposed granite density varies by binder chemistry and moisture content, weighing between 2,700 pounds (1.35 tons) per loose cubic yard for untreated natural stone up to 3,200 pounds (1.60 tons) per yard for polymer-stabilized and resin-coated aggregates.

Because stabilized DG blends include organic psyllium powder, liquid polymers, or clear binding resins, they consolidate with fewer open air voids than raw granite fines. This higher consolidation density increases the total weight required to cover every square foot.

When Natural Loose DG Is Not the Right Choice

We do not recommend natural, unstabilized decomposed granite for every application:

• Slopes Greater than 4% Grade: Natural DG will scour and wash out during heavy seasonal cloudbursts. Sloped transitions require polymer-stabilized DG or mechanical erosion stabilization grids.
• Direct Entryways with Hardwood Floors: Unbound granite fines stick to shoe soles and dog paws, acting like 60-grit sandpaper on indoor polyurethane flooring finishes. Entry-adjacent walkways require stabilized DG or an 8-foot buffer of clean flagstone.
• Under Tree Canopies with High Organic Droppings: Natural DG cannot be vigorously raked or power-blown without dislodging the unbonded granite surface.

How Much Does 1 Ton of Decomposed Granite Cover?

One short ton (2,000 lbs) of standard natural decomposed granite covers approximately 120 square feet at 2 inches compacted depth, 80 square feet at 3 inches compacted depth, and 60 square feet at 4 inches compacted depth when compacted to standard 95% density.

When planning your purchase order, use the following quick-reference matrix. These calculations include a standard 22% compaction shrinkage allowance and 3% perimeter edge-cutting waste:

How Much Does Decomposed Granite Cost Delivered? Bulk vs. Bagged

Bulk decomposed granite costs between $45 and $75 per ton for natural stone and $110 to $175 per ton for stabilized blends at the quarry, with regional freight delivery adding $125 to $250 flat per haul depending on travel mileage and truck classification.

Buying packaged 50-pound bags from retail home centers costs between $5.50 and $7.00 per bag. That equals roughly $0.11 to $0.14 per pound, or $220 to $280 per ton of material. Buying bulk aggregate directly or using our general Gravel Calculator for bulk estimating reduces your raw material cost by 65% to 75% on projects exceeding 2 tons.

Bulk Decomposed Granite Delivery Requirements: Access & Staging

Commercial bulk aggregate delivery requires a minimum clearance of 10 feet wide and 14 feet overhead, clear of utility wires and tree limbs, with drop locations restricted to approved concrete pads, asphalt, or street curbs protected by heavy woven tarps.

A tandem-axle dump truck carrying 12 to 16 tons of rock exerts substantial ground pressure. Drivers cannot cross residential lawns, uncompacted dirt, or decorative flagstone without causing rutting or cracked stone. If rain is forecast for your delivery window, rescheduling prevents unworkable, saturated aggregate from sitting on your site.

Commercial Delivery Vehicle Specifications:

• Single-Axle Bobtail Dump Truck (1 to 7 Short Tons): Requires 9.5 feet of horizontal vehicle width and 12 feet of overhead clearance. Designed specifically for tight residential cul-de-sacs, narrow city lanes, and short residential driveways.
• Tandem-Axle Dump Truck (8 to 16 Short Tons): Requires 10 feet of width and 14 feet of overhead travel clearance. During bed extension, the dump body reaches 22 feet into the air. Staging areas must remain clear of all overhead tree limbs, telephone drops, and power lines.
• End Dump / Transfer Trailer (17 to 25 Short Tons): Requires wide-radius turns and industrial-grade access roads. This equipment cannot execute residential driveway drops and operates exclusively on commercial job sites or designated street curbs with municipal permits.

Job-Site Preparation Checklist:

1. Mark the Drop Target: Lay down heavy-duty woven polyethylene tarps across the drop zone. This prevents loose aggregate from embedding into asphalt textures or staining light concrete.
2. Clear Vertical Envelopes: Inspect the drop path for hanging tree branches, low-hanging data cables, and gutter downspouts. Ensure a full 22 feet of vertical clearance directly above the designated dump point.
3. Protect Utilities and Irrigation: Flag buried water meters, irrigation sprinkler lines, and shallow utility cleanouts located within 5 feet of the truck tire path.

Need Turnkey Installation? Professional DG Grading & Compaction

Moving 10 tons of decomposed granite requires roughly 100 wheelbarrow loads and continuous mechanical plate compaction. Commercial site preparation and installation typically costs between $4.50 and $8.50 per square foot, depending on existing turf excavation depth, subgrade soil conditions, and site wheelbarrow access.

Professional installations require laser subgrade excavation, non-woven separation geotextile placement, heavy-gauge commercial 1/8″ steel bender board edging with anchored drive stakes, multi-lift moisture-conditioned spreading, and a final 1.5% positive drainage grading away from building foundations.

Frequently Asked Questions About Decomposed Granite Calculation & Installation

Why does decomposed granite turn muddy or wash out after heavy rains?

Natural DG softens when saturated if it lacks fine particles or proper drainage slope. To eliminate mud and rutting, install a stabilized DG blend containing organic or polymeric binders and ensure a minimum 1.5% cross-slope away from structures.

Should I install weed barrier geotextile fabric directly under decomposed granite?

No. Placing geotextile fabric directly beneath a thin 2-inch to 3-inch layer of decomposed granite prevents aggregate interlock and causes surface slipping. Place woven geotextile fabric beneath the compacted crushed stone sub-base layer, never directly beneath the finished DG surface.

Can I compact decomposed granite with a manual hand tamper?

Manual hand tampers only provide sufficient downward force for small patch repairs under 40 square feet. For patios, walkways, or driveways, you must use a minimum 3,000-pound vibratory plate compactor to achieve the 95% Proctor density required to resist erosion.

How do I calculate decomposed granite for curving or irregular landscape paths?

Break curved pathways into segmented geometric rectangles and arcs, calculate the square footage of each section, add them together, and increase your calculated tonnage by an extra 8% to 10% to account for perimeter cutting waste along edge restraints.

What is the difference between crushed granite gravel and decomposed granite?

Crushed granite gravel consists of uniform, washed stone chips without rock dust, which creates a loose, shifting surface. Decomposed granite includes a balanced ratio of 3/8-inch stone down to micro-fines, allowing the particles to lock together into a firm, walkable surface.

Related Material Calculators

Planning other areas of your outdoor hardscaping or landscaping project? Use our matching precision calculators to calculate exact materials across your property:

• Paver Base Calculator — calculate crushed stone base and bedding sand for interlocked pavers
• Sand Calculator — estimate concrete bedding sand and masonry sand requirements
• Rock Calculator — calculate decorative river rock and landscape stone tonnage
• Mulch Calculator — estimate shredded bark and garden mulch for planting beds
• Free Asphalt Calculator — calculate hot-mix asphalt tonnage for paved driveways