Decomposed Granite Calculator
Estimate Coverage, Cubic Yards, Tons & Cost for Pathways, Patios & Xeriscaping
How to Calculate Decomposed Granite
Calculating decomposed granite (DG) is straightforward once you know the three key values: area, depth, and density.
- Step 1 — Volume in Cubic Feet: Multiply Length × Width × Depth (all in feet). Example: 20 ft × 10 ft × 0.25 ft (3 in) = 50 cubic feet.
- Step 2 — Convert to Cubic Yards: Divide cubic feet by 27. 50 ÷ 27 ≈ 1.85 cubic yards.
- Step 3 — Convert to Tons: DG weighs approximately 2,700 lb per cubic yard (1.35 tons/yd³). 1.85 × 1.35 = 2.5 tons.
- Step 4 — Add Waste Factor: Add 10–15%. 2.5 × 1.10 = 2.75 tons to order.
Worked Example
Using the calculator's default inputs, here's a complete calculation from area to final cost:
Step-by-Step
Recommended Depth by Application
| Application | Recommended Depth | Notes |
|---|---|---|
| Decorative top-dress | 1–2 inches | Refreshing existing DG surface |
| Pathway / walkway | 3–4 inches | Most common; 3 in minimum for stability |
| Patio / seating area | 3–4 inches | Use stabilized DG binder for firmer surface |
| Driveway (passenger cars) | 4–6 inches | Compact in 2-inch lifts for best results |
| Xeriscaping / garden bed | 3–4 inches | Use landscape fabric for weed suppression |
| ⚠ Playground fall zones | DG not suitable | Decomposed granite is not a CPSC-recognized playground fall-surfacing material — it compacts and hardens over time. Use engineered wood fiber, rubber mulch, or another CPSC-tested material at 9 in. minimum depth (CPSC Publication 325). |
What Is Decomposed Granite (and Why Use It)?
Decomposed granite (DG) is a naturally weathered granite aggregate — solid granite that has broken down into fine, sand-like particles, typically graded to ⅜ inch or smaller. It’s sold in earth-tone colors (tan, gold, gray, red) determined by the parent rock, and has been a standard hardscape material in the Southwest and California for decades because of its natural look and low cost relative to pavers or poured concrete.
DG comes in three forms, each suited to a different use:
- Natural (loose) DG — no additives, the cheapest option, but it migrates, tracks indoors, and needs periodic replenishment and edging to hold its shape. Best for garden beds, low-traffic paths, and xeriscaping.
- Stabilized DG — a polymer binder is mixed in and compacted on-site, producing a firmer surface that holds up to regular foot traffic without the loose-material drawbacks. Lasts 5–10 years before refresh. Most common choice for pathways and patios.
- Resin-bound DG — a resin binder is mixed with the aggregate before installation, creating a solid-set, paved-feeling surface. The most durable and most expensive option, and the only one of the three generally suitable for vehicle traffic or ADA-compliant paths.
DG’s main advantage over mulch or bark is longevity — it doesn’t decompose or need annual replacement. Its main advantage over poured concrete or pavers is permeability: as a loose or semi-permeable aggregate, it lets rainwater infiltrate rather than run off, which is why it’s a common choice for xeriscaping and drought-tolerant landscape designs, and can help meet local stormwater or permeable-surface requirements in some jurisdictions.
The tradeoff is that unstabilized DG requires more upkeep than a hard surface — periodic top-offs, occasional compaction, and weed control (a landscape fabric underlayment is standard practice). Stabilized and resin-bound types significantly reduce that maintenance burden at a higher up-front cost.
DG Type Comparison — Natural vs. Stabilized vs. Resin-Bound
Choosing the right DG type depends on traffic level, budget, and how much maintenance you’re willing to do. The cost figures below match those in the DG Cost Guide in the sidebar.
| Type | Cost/Ton | Durability | Maintenance | Best For |
|---|---|---|---|---|
| Natural (loose) | $35–$60 | Erodes over time; annual top-off typical | High — migrates, needs edging & re-leveling | Garden beds, low-traffic paths, xeriscaping |
| Stabilized | $55–$85 | 5–10 years before refresh | Moderate — occasional resealing | Walkways, patios, medium-traffic areas |
| Resin-bound | $80–$130 | 15–20 years, most durable | Low | Driveways, high-traffic/commercial, ADA-compliant paths |
Material cost only. Installation labor adds $1–$4/sq ft depending on depth and site conditions. Resin-bound systems may require professional installation.
Frequently Asked Questions
How many tons of decomposed granite do I need for a 10x10 area?
At the standard 3-inch pathway depth: 10 ft × 10 ft × 3 in ÷ 324 = 0.93 cubic yards, or about 1.25 tons before waste. Add a 10% waste/compaction factor and plan to order roughly 1.4 tons. At 4 inches deep, that becomes approximately 1.84 tons with waste. Always round up when ordering — most suppliers sell in half-ton or full-ton increments.
How much does a cubic yard of decomposed granite weigh?
Natural DG weighs approximately 2,700 lb (1.35 tons) per cubic yard, though it can range 2,700–3,000 lb depending on moisture and particle size. Stabilized and resin-bound DG weigh somewhat more due to the added binder. When ordering from suppliers, convert your cubic yard estimate to tons using the 1.35 multiplier, then add your waste/compaction factor.
Can I use decomposed granite for a driveway?
Yes, for passenger-vehicle driveways, but it needs a compacted aggregate base beneath it, a greater depth (4–6 inches, compacted in 2-inch lifts), and ideally a stabilizer or resin binder — loose natural DG alone tends to rut and wash out under regular vehicle traffic. A plate compactor is essential. For heavy vehicles or frequent traffic, resin-bound DG is the most durable option.
What is the difference between stabilized and unstabilized DG?
Unstabilized (natural) DG is loose granite fines with no additives — cheapest, but it migrates, tracks indoors, and needs periodic replenishment and edging to hold its shape. Stabilized DG has a polymer binder mixed in and compacted on-site for a firmer, longer-lasting surface (5–10 years before refresh). Resin-bound DG uses a resin binder mixed in before installation, producing the most solid, durable surface at the highest cost ($80–$130/ton) — closest to a paved feel and the only form generally suitable for vehicle traffic or ADA-compliant paths.
Does decomposed granite need to be compacted?
Yes. DG should be compacted in place, typically in 2-inch lifts for depths over 3 inches, to reach a stable surface. Loose DG settles roughly 15–20% from its uncompacted volume, which is why the waste/compaction factor in the calculator above matters — it accounts for that settling, not just spillage. Use a hand tamper for small areas or a plate compactor for anything larger. Lightly moisten the surface first to help particles bind.
Sources & References
The depth recommendations, density constants, and playground surfacing caution used in this calculator are based on the following primary sources:
- CPSC Publication 325 — Public Playground Safety Handbook (2025 Edition) — Basis for the playground surfacing caution. DG is not on the CPSC list of impact-attenuating loose-fill materials; CPSC minimum depth for recognized materials is 9 inches. cpsc.gov (PDF)
- ASTM F1292 — Standard Specification for Impact Attenuation of Surfacing Materials for Playground Use Zones. Defines the test methodology for recognized fall-protection surfacing materials. astm.org
- NSSGA (National Stone, Sand & Gravel Association) — Industry density and material benchmarks for aggregate products; basis for the 2,700 lb/yd³ DG density reference. nssga.org
- University Cooperative Extension hardscape and xeriscape guidance — General basis for depth-by-application recommendations and stabilizer use. Consult your state’s extension service for regionally specific guidance on DG in drought-tolerant landscapes.