Decomposed Granite Calculator
Calculate tons of decomposed granite needed for a walkway or patio at your depth, using its 1.35 tons per cubic yard density.
How this calculator works
Decomposed granite is sold by the ton like other aggregates, so this calculator converts your path or patio’s area and depth into cubic yards, then multiplies by DG’s typical density of 1.35 tons per cubic yard to get the tons you need to order.
Formula: Cubic yards = (Length ft × Width ft × Depth ft) ÷ 27. Tons = Cubic yards × 1.35.
Worked example
A 15 ft × 10 ft path at a 3-inch depth:
- Depth in feet: 3 ÷ 12 = 0.25 ft
- Cubic yards: (15 × 10 × 0.25) ÷ 27 ≈ 1.389 yd³
- Tons: 1.389 × 1.35 ≈ 1.88 tons
- At $50/ton, that’s $93.75 before waste.
Coverage reference
| Depth | Coverage per ton |
|---|---|
| 2 in | ~120 sq ft |
| 3 in | ~80 sq ft |
| 4 in | ~60 sq ft |
How to measure your area
Measure the length and width of the finished path or patio surface, including any curves approximated as straight segments. Use the compacted depth you’re targeting, since DG settles somewhat once watered in and compacted from its loose-poured thickness.
Frequently asked questions
What is decomposed granite?
Decomposed granite (DG) is granite that has naturally weathered into a mix of small gravel-sized fragments and fine, sand-like particles. That blend of coarse and fine material is what lets it compact into a firm, natural-looking surface rather than staying loose like standard gravel.
Do I need to add a stabilizer to decomposed granite?
For light-traffic paths, plain DG compacted with water and a plate compactor holds up fine. For patios, driveways, or areas with heavier foot traffic, a resin stabilizer mixed in before compaction reduces erosion and keeps the surface from migrating over time.
How deep should a decomposed granite path be?
2-3 inches is standard for a walkway or garden path over a compacted subgrade. Patios or areas expecting more wear sometimes use two compacted lifts totaling 4 inches for added durability.
Why does decomposed granite compact differently than crushed stone?
Crushed stone like #57 is screened to a uniform particle size, so it stays loose and drains well. Decomposed granite keeps its natural mix of coarse fragments and fine dust, and those fines fill the gaps between larger pieces when compacted with moisture, locking the surface together.
Does decomposed granite need edging?
Yes, in most cases. Because DG compacts but isn't rigid like concrete, metal or plastic edging along the path's border keeps it from spreading or eroding into adjacent lawn or garden beds over time.
How often does a decomposed granite surface need to be refreshed?
Expect to top-dress a heavily used path every 2-4 years with a thin new layer, since foot traffic and rain gradually wear down and displace the surface fines that hold it together.
Estimates only. Verify quantities with your supplier before purchasing.