Decomposed Granite Calculator
Enter the path or patio size and finished depth.
Landscaping
Decomposed Granite Calculator
Quick answer: decomposed granite (tons) = length × width × depth in feet × (1 + compaction allowance) ÷ 27 × about 1.35 tons/yd³. A 30 ft × 3 ft stabilized path 3 in deep needs 27 ft³ of loose DG — 1.0 yd³, about 1.35 tons or 54 half-cubic-foot bags.
Size natural (loose) or stabilized decomposed granite for garden paths, patios, and tree rings. Results include the extra material lost to compaction, bulk tons and cubic yards for delivery, and bag counts for small jobs.
How to calculate decomposed granite
Decomposed granite is granite that has weathered into small particles — from about 1/4 in down to silt. Because it contains so many fines, it packs down noticeably when it is wetted and rolled. Calculate the finished volume first, then add a compaction allowance to get the loose amount you have to buy.
L × W × D (ft) × (1 + C) ÷ 27 × 1.35
= tons of DG, where C is the compaction allowance (about 0.20 stabilized, 0.10 loose)
- Measure the area. For a curved path, multiply the average width by the length measured along the centerline.
- Pick a finished depth from the table below and convert to feet (3 in = 0.25 ft).
- Multiply area × depth for the finished volume in cubic feet.
- Add compaction: × 1.20 for stabilized DG that is wetted and compacted, × 1.10 for loose DG that is only raked and rolled.
- Convert: ÷ 27 for cubic yards, × 1.35 for tons, or ÷ 0.5 for half-cubic-foot bags.
Worked example: stabilized DG patio
A 12 ft × 14 ft patio finished at 4 in with stabilized decomposed granite:
- Area: 12 × 14 = 168 ft²; finished volume: 168 × 0.333 = 56 ft³
- Loose volume with 20% compaction: 56 × 1.2 = 67.2 ft³ ÷ 27 = 2.49 yd³
- Weight: 2.49 × 1.35 = 3.36 tons
- Bags: 67.2 ÷ 0.5 = 134.4 → 135 bags; bulk cost at $60 per ton ≈ $202 plus delivery
DG depth guide and quantity per 100 ft²
Tons at 1.35 tons per yd³. Stabilized rows include a 20% compaction allowance, natural rows 10%. Bag counts are 0.5 ft³ bags, rounded up.
| Use | Finished depth | Type | Tons per 100 ft² | Bags per 100 ft² |
|---|---|---|---|---|
| Mulch-style top dressing, tree rings | 2 in | Natural | 0.92 | 37 |
| Garden path, light foot traffic | 2 in | Stabilized | 1.00 | 40 |
| Main walkway | 3 in | Natural | 1.38 | 55 |
| Main walkway, wheelchair or stroller use | 3 in | Stabilized | 1.50 | 60 |
| Patio, seating area, fire-pit area | 4 in | Stabilized | 2.00 | 80 |
Stabilized vs. natural decomposed granite
Natural (loose) DG is the plain crushed material. It is cheap and drains well, but it stays somewhat soft, tracks onto shoes, and washes out on slopes. It suits tree rings, dry-garden mulch, and low-traffic paths. Stabilized DG has a binder — usually a plant-based (psyllium) or polymer stabilizer — blended in at the yard. It is placed in lifts, soaked, and compacted with a plate compactor or roller, and cures into a firm surface that resists erosion and holds up to foot traffic and wheelbarrows. Resin-bound DG is a third option: a harder, near-pavement finish that is usually contractor-installed. For any stabilized product, follow the supplier's depth and watering instructions — they control the result more than the quantity does.
Both types need a firm base. On clay or soft soil, many installers put 2–4 in of compacted crusher run under patio-depth DG; estimate that layer with the crusher run calculator.
DG installation tips and common mistakes
- Going too thin. Under 2 in finished, DG wears through to the soil in a season. Use at least 3 in where people walk daily and 4 in for patios.
- Placing it all at once. Stabilized DG compacts best in 1.5–2 in lifts. A single 4 in lift stays soft at the bottom.
- No edging. DG migrates into lawns and beds. Steel, aluminum, or paver edging along the sides keeps the edges crisp and full depth.
- Ignoring drainage. Slope the surface about 2% (1/4 in per foot) away from buildings. Standing water softens even stabilized DG.
- Buying bags for a big job. At 0.5 ft³ per bag, one cubic yard is 54 bags. Above about a yard, bulk delivery is usually cheaper and much less handling.
- Using a generic density. Moisture changes weight. If your yard sells by the ton, ask what tons-per-yard figure they use and enter it.
Decomposed granite FAQ
How much decomposed granite do I need?
Multiply length × width × finished depth in feet, add about 20% for compaction on stabilized DG, and divide by 27 for cubic yards. Multiply by roughly 1.35 tons per yard for weight. A 30 × 3 ft path at 3 inches needs about 1 cubic yard, or 1.35 tons.
How deep should decomposed granite be?
Use about 2–3 inches for garden paths and walkways and 3–4 inches of stabilized DG for patios and seating areas. Light-duty driveways need a deeper compacted aggregate base under the DG; ask your supplier for a driveway spec. Thinner layers wear through quickly.
How much does a yard of decomposed granite weigh?
A cubic yard of decomposed granite typically weighs about 1.25 to 1.4 tons (2,500 to 2,800 lb), depending on moisture and gradation. This calculator uses 1.35 tons per yard by default; enter your supplier’s figure if it differs.
How many bags of decomposed granite equal a yard?
A cubic yard is 27 cubic feet, so it takes 54 bags of 0.5 cubic feet. Each 0.5 cubic foot bag weighs roughly 50 lb at typical density. For a project needing more than about one yard, bulk delivery is usually more economical than bags.
What is the difference between stabilized and loose decomposed granite?
Stabilized DG has a binder mixed in and is compacted wet, curing into a firm, erosion-resistant surface suited to patios and accessible paths. Loose or natural DG has no binder, stays softer, and can wash out on slopes. Stabilized DG needs more compaction, so plan about 20% extra material versus about 10% for loose.
How we built this calculator: results use the standard volume, area, and coverage formulas shown on this page, with typical U.S. material densities, bag yields, and waste factors that you can override. Written and checked by the YardsCalculator editorial team. Last reviewed: October 2026.