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Bags of River Rock for a 6x75 Walkway

How many bags of river rock for a 6x75 walkway: at 3 inches deep you need about 112.5 cubic feet, which is 225 bags of the common 0.5 cubic foot size. If your store sells river rock in 50-pound bags instead, figure about 225 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 in37.57575
2 in75.0150150
3 in112.5225225
4 in150.0300300

How to figure it

  1. Area: 6 × 75 = 450 sq ft.
  2. Volume: 450 × (3 ÷ 12) = 112.5 cu ft.
  3. Bags: 112.5 ÷ 0.5 = 225 bags (round up).

Bags or bulk?

A cubic yard is 27 cubic feet, so 112.5 cubic feet is 4.17 yards, about 5.6 tons. Past about a yard, bulk is usually less work and often less money. Compare the bag price × 225 against a bulk quote for 6.2 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.

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 8x16 area at 3 inches takes about 1.6 tons.
  • Weight used here: about 1.35 tons per cubic yard.

Where estimates go wrong

  • 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.
  • Mixing up cubic yards and tons. Yards are volume, tons are weight; convert with the product’s weight per yard.
  • Ordering exactly the math. Uneven ground and spillage nearly always need a little more than the flat calculation.

Questions people ask

How many bags of river rock for a 6x75 walkway?

About 225 bags of 0.5 cubic feet at 3 inches deep.

How many 50 lb bags of river rock for 6x75?

About 225 bags at 3 inches.

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

54 bags.

How many cubic feet is a 6x75 walkway at 3 inches?

About 112.5 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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