Calculator 07 / 08
River rock calculator
River rock is larger and rounder than gravel, so depth choice matters more. Measure the run, pick a depth that covers the stone, and order by yard or ton.
- Outputs
- yd³ · tons · tonnes · bags · cost
- Material basis
- River rock · 105 lb/ft³ default, editable
- Method
- Formulas & sources
Where river rock goes
River rock is smooth, water-rounded stone, usually larger than gravel. It is chosen for looks and for places water runs: dry creek beds, downspout outlets, swales and borders. Because the pieces are large, the layer has to be deep enough for stones to overlap and hide the ground or fabric underneath.
For a channel, measure the width across the top and use an average depth. For an irregular run, split it into sections.
Worked example: dry creek bed
| Run | 40 ft × 3 ft = 120 ft², average 4 in deep |
|---|---|
| Volume | 40 ft³ = 1.48 yd³ |
| + Waste 10% | 44 ft³ = 1.63 yd³ |
| Weight | ≈ 2.31 US tons at 105 lb/ft³ |
Weight of river rock
We found no reliable published density specific to river rock, so the general dry-gravel value (105 lb/ft³) source is used, with the published gravel range source shown for context. Large rounded stones leave more space between them than finer material, and suppliers' river rock products vary widely in size, so the weight is approximate. If the supplier quotes “tons per yard” for the product, enter it.
Questions
How much river rock do I need?
Area × average depth gives cubic feet; divide by 27 for cubic yards. Add a waste allowance. The calculator converts to tons with an editable density.
How deep should river rock be?
Deep enough that stones overlap and hide what's underneath. Larger stone needs a deeper layer. Try your planned depth and a deeper one to see the difference in the order.
Does river rock weigh the same as gravel?
Not exactly. It's the same kind of material, but size and shape change how tightly it packs. We use the general gravel value by default because we don't have a reliable river-rock-specific figure.