How Much River Rock for a 4x100 Walkway?
How much river rock for a 4x100 walkway: at 3 inches deep you need about 3.70 cubic yards, which is roughly 5.0 tons at 1.35 tons per yard. The walkway covers 400 square feet, so every inch of depth adds about 1.23 yards.
Volume and tonnage calculator →The math for a 4x100 walkway
- Area: 4 × 100 = 400 sq ft.
- Depth in feet: 3 ÷ 12 = 0.250 ft.
- Cubic feet: 400 × 0.250 = 100.0 cu ft.
- Cubic yards: ÷ 27 = 3.70 yd³.
- Tons: × 1.35 = 5.0 tons.
The volume and tonnage calculator does this for any size.
River rock needed by depth
| Depth | Cubic yards | Tons (approx.) | Tons +10% |
|---|---|---|---|
| 2 in | 2.47 | 3.3 | 3.7 |
| 3 in | 3.70 | 5.0 | 5.5 |
| 4 in | 4.94 | 6.7 | 7.3 |
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. Ask your supplier for their own tons-per-yard figure, since stone source and moisture shift it.
Preparing the walkway
Dig the path a few inches below grade, compact the bottom, add fabric if needed and install edging on both sides so the material stays on the walk. Since the walkway carries foot traffic, a little extra depth is cheap insurance.
Ordering tips
- Round up. Compaction and uneven ground eat material. Adding about 10 percent is common.
- Delivery size. 5.5 tons fits in a single typical dump truck load; small loads may carry a delivery fee. See how many tons of gravel in a dump truck.
- Bulk vs bags. At this size bulk delivery is usually the practical choice.
- Where it drops. Have the truck dump as close to the walkway as firm ground allows.
Where river rock fits
Works well for:
- Dry creek beds and drainage swales
- Decorative borders and planting beds
- Around downspouts to stop splash erosion
Poor fit 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 20x25 area at 4 inches takes about 8.3 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.
- Skipping drainage. Water sitting under any surface softens the base and leads to ruts and potholes.
- 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 tons of river rock for a 4x100 walkway?
About 5.0 tons at 3 inches deep, or 5.5 tons with 10 percent extra.
How many cubic yards is a 4x100 walkway at 3 inches?
About 3.70 cubic yards.
How much does a cubic yard of river rock weigh?
Usually around 1.25 to 1.45 tons, depending on stone size, fines and moisture.
How deep should river rock be for a walkway?
The table above shows 2 to 4 inches. Shallower depths suit top dressing; deeper depths suit new installs and heavier use.
How many square feet is 4x100?
400 square feet.
Related guides
- How Much Does a Ton of River Rock Cover?
- Tons to Cubic Yards for Gravel: Conversion Chart
- How Many Tons of Gravel in a Dump Truck? Loads and Coverage
- How Much Does a Ton of Gravel Cover? Depth Chart
- How Much River Rock for a 4x60 Walkway?
- How Much River Rock for a 4x75 Walkway?
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