River rock for a 12×12 ft garden bed
A 12 × 12 ft garden bed at 2 in deep needs 0.89 cubic yards of river rock, roughly 1.08 tons and $93.33 of material. Fine-tune below.
Full breakdown
| Item | Value |
|---|---|
| Volume before waste | 24.0 ft³ |
| Volume with 10% waste | 26.4 ft³ |
| Cubic yards | 0.98 |
| Cubic metres | 0.75 |
| Cubic feet | 26.4 |
| Weight | 1.19 tons (2,376 lb) |
| Full dump-truck loads | 1 × 10 yd³ truck |
| Sq ft covered at 1 in deep | 317 |
| Sq ft covered at 3 in deep | 106 |
- Formula: length × width × depth, with depth converted from inches to feet (÷ 12), then × (1 + waste%).
- River Rock: River rock is decorative rounded stone sold by the cubic yard or in bags; the size grade (3/4 inch, 1–3 inch, 3–5 inch) matters more than the colour for coverage.
- Bigger stone covers less area per yard because the voids between the rocks are larger — a 3–5 inch grade needs roughly 20% more volume than pea gravel for the same depth.
- Prices are national averages for planning, not quotes. Confirm with a local supplier — delivery, short-load fees and tax are extra.
For a 12 × 12 ft garden bed at 2 in, you need 0.89 cubic yards of river rock (24.0 ft³, about 1.08 tons) before any extra you add for waste.
The calculator above is pre-filled with these dimensions — change any field to see the numbers update. River rock is decorative rounded stone sold by the cubic yard or in bags; the size grade (3/4 inch, 1–3 inch, 3–5 inch) matters more than the colour for coverage.
Frequently asked questions
How many cubic yards of river rock for a 12×12 ft garden bed?
About 0.89 cubic yards at 2 in deep, which is 24.0 cubic feet or 1.08 tons. Add 10% waste if the ground is uneven.
How many bags is that?
River Rock is normally sold in bulk by the cubic yard rather than by the bag, so order 0.89 yards. Bagged versions exist at garden centres but cost several times more per cubic foot.
What depth should a garden bed be?
2 in is the standard for river rock in this application. Bigger stone covers less area per yard because the voids between the rocks are larger — a 3–5 inch grade needs roughly 20% more volume than pea gravel for the same depth.