Decomposed granite calculator
A path 40 ft long and 4 ft wide, 3 in deep once compacted, takes about 2.40 tons of decomposed granite: 1.78 cubic yards loose, with 20% extra for compaction, or 96 half-cubic-foot bags.
How much decomposed granite you need
Decomposed granite, or DG, is granite weathered down to coarse sand and small chips, usually ⅜ in and finer. It packs hard when it's wetted and rolled, so a path loses depth as it's compacted. Kafka Granite, which quarries and sells decomposed granite, tells installers to allow 20 to 25% for compaction, and the calculator adds 20% unless you choose more. To finish at 3 in, you spread about 3.6 in loose.
The weight depends on the stone and how wet it is. Earth Stone Rock sells DG at about 2,700 lb a cubic yard, 1.35 tons, which the calculator uses. A Colorado supplier, Front Range Material, lists crusher fines, a similar product, at 1.5 tons a yard loose. If your yard gives a weight per yard, enter it; if it sells by the yard, choose that under Prices and the tons don't matter.
| Area | 2 in compacted | 3 in | 4 in | Bags at 3 in |
|---|---|---|---|---|
| 3 × 20 ft path | 0.60 | 0.90 | 1.20 | 36 |
| 4 × 40 ft path | 1.60 | 2.40 | 3.20 | 96 |
| 10 × 10 ft patio | 1.00 | 1.50 | 2.00 | 60 |
| 12 × 16 ft patio | 1.92 | 2.88 | 3.84 | 116 |
| 16 × 20 ft patio | 3.20 | 4.80 | 6.40 | 192 |
| 10 × 50 ft drive | 5.00 | 7.50 | 10.00 | 300 |
One ton covers about 100 sq ft at 2 in compacted, 67 sq ft at 3 in and 50 sq ft at 4 in.
Area: 40 ft × 4 ft = 160 sq ft
160 sq ft × 3 in = 40 cu ft × 1.2 = 48 cu ft ÷ 27 = 1.78 cu yd
1.78 cu yd × 2,700 lb ÷ 2,000 = 2.40 tons
How deep to lay it
Kafka Granite's pathway specification calls for at least 3 in of compacted DG where people walk and 4 in where vehicles drive. Earth Stone Rock suggests 2 to 3 in for paths and patios and 3 to 4 in for driveways, with a stabilizer mixed in. Deeper than that, lay and compact it in layers of no more than 3 or 4 in so each one packs fully.
Under the DG goes a compacted gravel subbase: 4 to 6 in for foot traffic and 8 to 12 in for vehicles, compacted to 95%, in Kafka's specification. For the 4 × 40 ft path above, a 4 in subbase is about 3.75 tons of crusher run; the crushed stone calculator works it out for your size. Edge the path with steel, aluminum or stone so the DG doesn't spread into the lawn.
Stabilized or loose
Plain DG stays loose on top and washes on slopes. Stabilized DG has a binder mixed in, so it sets firmer and holds up better to rain and wheels; it costs more and must be laid and compacted while damp, before the binder sets. Resin-bound DG sets harder still. The quantities are the same for all three.
Bags or bulk
Garden centers sell DG in bags of half a cubic foot, 40 to 50 lb. A ton is about 40 bags of 0.5 cu ft at 2,700 lb a yard, so bags make sense for a small patch and bulk for anything bigger than a cubic yard or so. Landscape yards sell it by the ton or the cubic yard, often with a delivery charge.
| Item | Typical | Range | Stores |
|---|---|---|---|
| 0.5 cu ft bag of decomposed granite | $7.62 | $4.69 to $10.99 | 4 |
For a looser, rounder surface that doesn't pack down, look at the pea gravel calculator; for other decorative stone, the landscape rock calculator. To change between tons and yards for any material, use tons to cubic yards.
What you'll need
- Steel or aluminum landscape edging keeps the decomposed granite from spreading into the lawn or beds.
- A landscape rake spreads each layer to an even depth before you compact it.
- A hand tamper compacts a small path; rent a plate compactor for a patio or driveway.
- A hose-end spray nozzle dampens each layer before tamping, which helps it pack hard.
Sources
- Standard pathway specification, Kafka Granite, April 2023. Allow 20 to 25% for compaction; at least 3 in compacted for paths and 4 in for vehicles; a 4 to 6 in subbase for foot traffic and 8 to 12 in for vehicles, compacted to 95%.
- Decomposed granite: coverage and depth, Earth Stone Rock, read November 2026. About 2,700 lb (1.35 tons) a cubic yard; 2 to 3 in deep for paths and patios, 3 to 4 in for driveways with stabilizer.
- Coverage and conversion chart, Front Range Material, current sheet. Crusher fines 1.5 tons a cubic yard loose and 1.8 compacted; riprap 1.65 tons a cubic yard.
- Weight-Volume Relationships and Conversion Factors for Soils and Aggregates of Wisconsin (WHRP 0092-22-05), Wisconsin Highway Research Program, Michigan State University, December 2023. Measured loose and compacted weights of base aggregates, recycled asphalt and recycled concrete; tons per compacted cubic yard.
- Online store listings for bagged concrete, mortar, grout, block, rebar, mesh, gravel, sand, soil, mulch and pavers, Google Shopping results (Home Depot, Lowe's, Menards, Ace Hardware, Walmart and others), November 2026. Single-item prices by store; the calculators use the median as the default and show the range.