Decomposed Granite Calculator

Decomposed granite (DG) for paths and patios: volume and tons for your area and depth, with extra built in for the way DG compacts.

Decomposed granite (DG) is granite weathered into small particles and fine grit. Laid and compacted, it makes a firm, natural-looking surface for paths, patios and around trees, popular in dry climates. It's sold loose, stabilised (mixed with a binder that sets) or with resin. Because DG compacts considerably when you wet it and roll or tamp it, you need more loose material than the finished depth suggests, so this calculator adds 15% by default. Enter the area and the finished depth and it gives the cubic yards or m³, the tons or tonnes, and the bags.

Units
Bag sizes
Area
ft
ft
in
Feet and inches work too: type 12'6 or 12.5.
t/yd³
%
Compacts noticeably, so allow extra.
Volume
1.28 yd³

34.5 ft³ · 0.977 m³

Weight
1.61 tons

3,220 lb · 1.46 tonnes

Bags
69

0.5 ft³ bag

Bags needed by size
0.5 ft³ bag69
20 kg bag74
25 kg bag59
How it was worked out
  1. Area: 12 ft × 10 ft = 120 ft²; × 3 in (0.25 ft) deep = 30 ft³
  2. 30 ft³ ÷ 27 = 1.11 yd³
  3. Plus 15% extra = 1.28 yd³
  4. 1.28 yd³ × 1.26 tons per yd³ = 1.61 tons (3,220 lb)
  5. 34.5 ft³ ÷ 0.5 ft³ per bag = 69, rounded up to 69 bags
Typical weights of common materials
Materialt/m³tons/yd³lb/ft³
Concrete2.402.02150
Gravel1.601.35100
Pea gravel1.601.35100
Crushed stone / crushed rock1.601.35100
River rock1.501.2694
Landscape rock / pebbles1.501.2694
Crushed limestone1.601.35100
Decomposed granite1.501.2694
Crusher run1.601.35100
Road base1.701.43106
Crusher dust1.501.2694
Aggregate (20 mm)1.601.35100
All-in ballast1.651.39103
MOT Type 1 sub-base1.801.52112
Sand1.601.35100
Topsoil1.301.1081
Garden soil1.301.1081
Fill dirt1.401.1887
Mulch0.350.2922
Bark chippings0.300.2519
Asphalt (compacted)2.321.96145

Loose, as-delivered figures; asphalt and concrete are as laid. Moisture, stone size and source change the real weight, so use your supplier's figure when you have it. Tons are US short tons (2,000 lb).

Common use cases

  • Garden paths and walkways
  • Patios and seating areas
  • Surfacing around trees and between pavers
  • Pathways in drought-tolerant gardens

How to use

  1. Choose feet and inches or metres and millimetres, and the country whose bag sizes you want.
  2. Enter the length and width of the area, or switch the shape to a circle, triangle or a known area. Use Add another area for L-shapes and separate beds.
  3. Enter the depth of DG. Paths are commonly 2 to 3 inches (50 to 75 mm) deep after compaction, over a firm base.
  4. Check the density and the extra allowance. Change the density if your supplier quotes a different figure.
  5. Read the volume, weight and bag count, and add a price per ton, cubic yard, m³ or bag for a cost estimate.

FAQ

How deep should decomposed granite be?

Around 2 to 3 inches (50 to 75 mm) compacted for foot traffic, laid in layers that are each dampened and compacted. Areas that take vehicles need a deeper compacted base underneath.

How much extra DG should I allow?

It compacts noticeably, so many people allow 10 to 20% more than the finished volume. The calculator starts at 15%.

How much does decomposed granite weigh?

Loose DG is roughly 1.25 tons per cubic yard (1.5 tonnes per m³), more when wet or compacted. Use your supplier's figure if they give one.

Related tools