Bags of Decomposed Granite for a 4x20 Walkway
How many bags of decomposed granite for a 4x20 walkway: at 3 inches deep you need about 20.0 cubic feet, which is 40 bags of the common 0.5 cubic foot size. If your store sells decomposed granite in 50-pound bags instead, figure about 40 bags, since decomposed granite weighs roughly 100 pounds per cubic foot.
Volume and tonnage calculator →Bag count by depth
| Depth | Cubic feet | 0.5 cu ft bags | 50 lb bags (approx.) |
|---|---|---|---|
| 1 in | 6.7 | 14 | 14 |
| 2 in | 13.3 | 27 | 27 |
| 3 in | 20.0 | 40 | 40 |
| 4 in | 26.7 | 54 | 54 |
How to figure it
- Area: 4 × 20 = 80 sq ft.
- Volume: 80 × (3 ÷ 12) = 20.0 cu ft.
- Bags: 20.0 ÷ 0.5 = 40 bags (round up).
Bags or bulk?
A cubic yard is 27 cubic feet, so 20.0 cubic feet is 0.74 yards, about 1.0 tons. This is a small enough job that bags are reasonable, especially if a bulk delivery fee applies. Compare the bag price × 40 against a bulk quote for 1.1 tons delivered.
About decomposed granite
Decomposed granite (DG) is weathered granite broken into small particles and fines. It packs into a firm, natural-looking path surface, and stabilized versions include a binder.
Install tips for a walkway
- Dig and level. Remove sod and set the base slightly below the surrounding grade.
- Edge it. Steel, plastic or stone edging keeps material in place.
- Spread in layers. Rake to depth, then tamp or wet and compact.
- Buy a few extra. Grab 5 to 10 percent more bags for settling and touch-ups.
The volume and tonnage calculator handles other sizes and depths.
When to choose decomposed granite
Good uses:
- Garden paths and patios with a natural look
- Around trees and in xeriscape designs
- Stabilized DG for accessible paths
Less suited to:
- Steep grades without a stabilizer
- Areas right outside doors, since fines track in
- Driveways with heavy turning traffic
Quick reference numbers
- Per inch over 100 sq ft: about 0.42 tons of decomposed granite (0.31 cubic yards).
- Per inch over 1,000 sq ft: about 4.2 tons.
- Another size for comparison: a 10x20 area at 4 inches takes about 3.3 tons.
- Weight used here: about 1.35 tons per cubic yard.
Common estimating mistakes
- Mixing up cubic yards and tons. Yards are volume, tons are weight; convert with the product’s weight per yard.
- Using inches as if they were feet. Depth has to be divided by 12 before you multiply; skipping that step inflates the order twelvefold.
- Assuming every supplier uses the same weight. Two yards selling the same product name can quote different tons per yard.
- Skipping drainage. Water sitting under any surface softens the base and leads to ruts and potholes.
Questions people ask
How many bags of decomposed granite for a 4x20 walkway?
About 40 bags of 0.5 cubic feet at 3 inches deep.
How many 50 lb bags of decomposed granite for 4x20?
About 40 bags at 3 inches.
How many 0.5 cubic foot bags are in a cubic yard?
54 bags.
How many cubic feet is a 4x20 walkway at 3 inches?
About 20.0 cubic feet.
When does bulk make more sense?
Usually once the job passes about a cubic yard, or when you would need more than a few car trips.
Related guides
- Crushed Stone vs Gravel: Differences and Best Uses
- Tons to Cubic Yards for Gravel: Conversion Chart
- How Much Does a Ton of Gravel Cover? Depth Chart
- Bags of Decomposed Granite for a 4x10 Walkway
- Bags of Decomposed Granite for a 4x15 Walkway
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