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Bags of River Rock for a 5x100 Walkway

How many bags of river rock for a 5x100 walkway: at 3 inches deep you need about 125.0 cubic feet, which is 250 bags of the common 0.5 cubic foot size. If your store sells river rock in 50-pound bags instead, figure about 250 bags, since river rock weighs roughly 100 pounds per cubic foot.

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Bag count by depth

DepthCubic feet0.5 cu ft bags50 lb bags (approx.)
1 in41.78484
2 in83.3167167
3 in125.0250250
4 in166.7334334

How to figure it

  1. Area: 5 × 100 = 500 sq ft.
  2. Volume: 500 × (3 ÷ 12) = 125.0 cu ft.
  3. Bags: 125.0 ÷ 0.5 = 250 bags (round up).

Bags or bulk?

A cubic yard is 27 cubic feet, so 125.0 cubic feet is 4.63 yards, about 6.3 tons. Past about a yard, bulk is usually less work and often less money. Compare the bag price × 250 against a bulk quote for 6.9 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.

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 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.

When to choose river rock

Good uses:

  • Dry creek beds and drainage swales
  • Decorative borders and planting beds
  • Around downspouts to stop splash erosion

Less suited to:

  • 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 14x28 area at 2 inches takes about 3.3 tons.
  • Weight used here: about 1.35 tons per cubic yard.

Common estimating mistakes

  • Ordering exactly the math. Uneven ground and spillage nearly always need a little more than the flat calculation.
  • Forgetting that compaction shrinks loose material. A loose 4-inch spread of a dense-graded stone may finish closer to 3 inches after rolling.
  • Ignoring the base. A thin surface layer over soft soil fails early no matter how much material is on top.
  • Assuming every supplier uses the same weight. Two yards selling the same product name can quote different tons per yard.

Questions people ask

How many bags of river rock for a 5x100 walkway?

About 250 bags of 0.5 cubic feet at 3 inches deep.

How many 50 lb bags of river rock for 5x100?

About 250 bags at 3 inches.

How many 0.5 cubic foot bags are in a cubic yard?

54 bags.

How many cubic feet is a 5x100 walkway at 3 inches?

About 125.0 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

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