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Bags of River Rock for a 5x75 Walkway

How many bags of river rock for a 5x75 walkway: at 3 inches deep you need about 93.8 cubic feet, which is 188 bags of the common 0.5 cubic foot size. If your store sells river rock in 50-pound bags instead, figure about 188 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 in31.26363
2 in62.5125125
3 in93.8188188
4 in125.0250250

How to figure it

  1. Area: 5 × 75 = 375 sq ft.
  2. Volume: 375 × (3 ÷ 12) = 93.8 cu ft.
  3. Bags: 93.8 ÷ 0.5 = 188 bags (round up).

Bags or bulk?

A cubic yard is 27 cubic feet, so 93.8 cubic feet is 3.47 yards, about 4.7 tons. At this size, a bulk delivery usually beats a cart full of bags once you count trips. Compare the bag price × 188 against a bulk quote for 5.2 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.

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.

Good and poor uses for river rock

Works well for:

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

Common estimating mistakes

  • Measuring only the main rectangle. Aprons, turnouts and curved edges add real square footage.
  • Ordering exactly the math. Uneven ground and spillage nearly always need a little more than the flat calculation.
  • Using inches as if they were feet. Depth has to be divided by 12 before you multiply; skipping that step inflates the order twelvefold.
  • Mixing up cubic yards and tons. Yards are volume, tons are weight; convert with the product’s weight per yard.

Questions people ask

How many bags of river rock for a 5x75 walkway?

About 188 bags of 0.5 cubic feet at 3 inches deep.

How many 50 lb bags of river rock for 5x75?

About 188 bags at 3 inches.

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

54 bags.

How many cubic feet is a 5x75 walkway at 3 inches?

About 93.8 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

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