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Bags of River Rock for a 4x50 Walkway

How many bags of river rock for a 4x50 walkway: at 3 inches deep you need about 50.0 cubic feet, which is 100 bags of the common 0.5 cubic foot size. If your store sells river rock in 50-pound bags instead, figure about 100 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 in16.73434
2 in33.36767
3 in50.0100100
4 in66.7134134

How to figure it

  1. Area: 4 × 50 = 200 sq ft.
  2. Volume: 200 × (3 ÷ 12) = 50.0 cu ft.
  3. Bags: 50.0 ÷ 0.5 = 100 bags (round up).

Bags or bulk?

A cubic yard is 27 cubic feet, so 50.0 cubic feet is 1.85 yards, about 2.5 tons. At this size, a bulk delivery usually beats a cart full of bags once you count trips. Compare the bag price × 100 against a bulk quote for 2.8 tons delivered.

About river rock

River rock is smooth, water-worn stone sold in sizes from about 3/4 inch to several inches. Larger sizes cover fewer square feet per ton at the same depth because the voids between stones are bigger.

Before you spread 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 10x20 area at 4 inches takes about 3.3 tons.
  • Weight used here: about 1.35 tons per cubic yard.

Where estimates go wrong

  • Mixing up cubic yards and tons. Yards are volume, tons are weight; convert with the product’s weight per yard.
  • Skipping drainage. Water sitting under any surface softens the base and leads to ruts and potholes.
  • 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.

Questions people ask

How many bags of river rock for a 4x50 walkway?

About 100 bags of 0.5 cubic feet at 3 inches deep.

How many 50 lb bags of river rock for 4x50?

About 100 bags at 3 inches.

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

54 bags.

How many cubic feet is a 4x50 walkway at 3 inches?

About 50.0 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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