Bags of River Rock for a 5x15 Walkway
How many bags of river rock for a 5x15 walkway: at 3 inches deep you need about 18.8 cubic feet, which is 38 bags of the common 0.5 cubic foot size. If your store sells river rock in 50-pound bags instead, figure about 38 bags, since river rock 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 | 6.2 | 13 | 13 |
| 2 in | 12.5 | 25 | 25 |
| 3 in | 18.8 | 38 | 38 |
| 4 in | 25.0 | 50 | 50 |
How to figure it
- Area: 5 × 15 = 75 sq ft.
- Volume: 75 × (3 ÷ 12) = 18.8 cu ft.
- Bags: 18.8 ÷ 0.5 = 38 bags (round up).
Bags or bulk?
A cubic yard is 27 cubic feet, so 18.8 cubic feet is 0.69 yards, about 0.9 tons. Under a yard, bags save a delivery fee and are easy to haul in a car or pickup. Compare the bag price × 38 against a bulk quote for 1.0 tons delivered.
About river rock
River rock is mostly decorative and for drainage beds. It is not meant to be driven on and tends to roll if used as a walking surface.
Laying it down 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 rake smooth; rounded stone will not 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.
Where river rock fits
Works well for:
- Dry creek beds and drainage swales
- Decorative borders and planting beds
- Around downspouts to stop splash erosion
Think twice for:
- Walking surfaces
- Driveways
- Bases under slabs or pavers
Quick reference numbers
- Per inch over 100 sq ft: about 0.42 tons of river rock (0.31 cubic yards).
- Per inch over 1,000 sq ft: about 4.2 tons.
- Another size for comparison: a 15x30 area at 4 inches takes about 7.5 tons.
- Weight used here: about 1.35 tons per cubic yard.
Where estimates go wrong
- Measuring only the main rectangle. Aprons, turnouts and curved edges add real square footage.
- Assuming every supplier uses the same weight. Two yards selling the same product name can quote different tons per yard.
- Ignoring the base. A thin surface layer over soft soil fails early no matter how much material is on top.
- Skipping drainage. Water sitting under any surface softens the base and leads to ruts and potholes.
Questions people ask
How many bags of river rock for a 5x15 walkway?
About 38 bags of 0.5 cubic feet at 3 inches deep.
How many 50 lb bags of river rock for 5x15?
About 38 bags at 3 inches.
How many 0.5 cubic foot bags are in a cubic yard?
54 bags.
How many cubic feet is a 5x15 walkway at 3 inches?
About 18.8 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
- How Much Does a Ton of River Rock Cover?
- Tons to Cubic Yards for Gravel: Conversion Chart
- How Much Does a Ton of Gravel Cover? Depth Chart
- Bags of River Rock for a 4x100 Walkway
- Bags of River Rock for a 5x10 Walkway
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