How Much River Rock for a 16x18 Patio?
A 16 by 18 foot patio is 288 square feet. How much river rock for a 16x18 patio depends on depth: at 3 inches it is about 2.67 cubic yards or 3.6 tons. Suppliers usually sell by the ton, so the tonnage is the number to give them.
Volume and tonnage calculator →The math for a 16x18 patio
- Area: 16 × 18 = 288 sq ft.
- Depth in feet: 3 ÷ 12 = 0.250 ft.
- Cubic feet: 288 × 0.250 = 72.0 cu ft.
- Cubic yards: ÷ 27 = 2.67 yd³.
- Tons: × 1.35 = 3.6 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 | 1.78 | 2.4 | 2.6 |
| 3 in | 2.67 | 3.6 | 4.0 |
| 4 in | 3.56 | 4.8 | 5.3 |
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. If the yard sells by the cubic yard instead of the ton, use the cubic-yard column directly.
Preparing the patio
Remove sod, level the area with a slight slope away from the house, and lay landscape fabric if weeds are a concern. Edging keeps loose material inside the patio footprint. For foot traffic and furniture, the depths in the table above are a reasonable starting range.
Ordering tips
- Round up. Compaction and uneven ground eat material. Adding about 10 percent is common.
- Delivery size. 4.0 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 patio as firm ground allows.
Good and poor uses for river rock
Good uses:
- 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 12x24 area at 3 inches takes about 3.6 tons.
- Weight used here: about 1.35 tons per cubic yard.
Mistakes that throw off the order
- Forgetting that compaction shrinks loose material. A loose 4-inch spread of a dense-graded stone may finish closer to 3 inches after rolling.
- Ordering exactly the math. Uneven ground and spillage nearly always need a little more than the flat calculation.
- 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.
Questions people ask
How many tons of river rock for a 16x18 patio?
About 3.6 tons at 3 inches deep, or 4.0 tons with 10 percent extra.
How many cubic yards is a 16x18 patio at 3 inches?
About 2.67 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 patio?
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 16x18?
288 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 16x14 Patio?
- How Much River Rock for a 16x16 Patio?
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