🪨 Stone Mulch Calculator
Calculate exactly how much decorative stone, gravel, or rock mulch you need for any project
| Depth | Sq Ft Covered | Sq M Covered | Depth (cm) |
|---|---|---|---|
| 1 in | 324 | 30.1 | 2.5 |
| 2 in | 162 | 15.1 | 5.1 |
| 3 in | 108 | 10.0 | 7.6 |
| 4 in | 81 | 7.5 | 10.2 |
| 6 in | 54 | 5.0 | 15.2 |
| Bag Size | Volume per Bag | Bags per Cubic Yard | Coverage at 3 in |
|---|---|---|---|
| Small Bag | 0.5 cu ft | 54 | 2 sq ft |
| Medium Bag | 1 cu ft | 27 | 4 sq ft |
| Large Bag | 2 cu ft | 13.5 | 8 sq ft |
| Extra Large Bag | 3 cu ft | 9 | 12 sq ft |
| Project | Area (sq ft) | Cubic Yards | Bags (2 cu ft) |
|---|---|---|---|
| Small Tree Ring | 28 | 0.26 | 4 |
| Front Bed | 100 | 0.93 | 13 |
| Side Yard Path | 200 | 1.85 | 25 |
| Medium Garden | 500 | 4.63 | 63 |
| Large Patio Area | 625 | 5.79 | 79 |
| Full Front Yard | 1,000 | 9.26 | 125 |
| Half-Acre Coverage | 2,500 | 23.15 | 313 |
One cubic yard of crushed stone cover around 108 square feet at 3 inches of depth, and it weighs almost 2 700 pounds. That beats a whole ton for only one yard. River stone weighs a bit less, close to 2 600 pounds, but the difference barely matters when you load a truck.
Lava stone is the exception with around 1 500 pounds per yard, which eases the move a lot.
How Much Stone You Need and the Good and Bad Things About It
For a bed of 500 square feet at 3 inches I ended up at around 4.6 yards. Say 5 with extra. At 2 inches the same area needs only 3.1 yards, which shows a 33 percent drop in material.
A really big change. If you go thicker to 4 inches, then it arrives at about 6.2 yards, so the depth is the main factor.
Decomposed granite is the heaviest material that I worked with, reaching 3 000 pounds per cubic yard. Slate pieces come in at around 2 800 puonds. On slopes I found that you need 15-20 percent extra because of gravity, which simply pulls the material down over time; 10 percent does not work for that job.
The info below does not come from some calculator or tool. It is based on real use, looking back, forum talks and experiences from garden groups across the net.
stone beds become more and more popular in landscaping, although they do not work for every case. Crushed stones work as mulch around fancy trees and bushes. They block unwanted grasses, keep the ground moist and protect roots against harsh temperatures.
Once in place, such rocky covering needs only little care to stay nice. The stones do not attract insects and do not suffer from mold or fungus.
stone, unlike wooden mulch, does not fade in colour after placing. It does not need refill and does not wash away during rains. Rocks and stone walls keep their order for much longer than just mulch.
Over the long run, stone ends up cheaper, although the starting cost is bigger.
Lava stones are liked, especially in dry regions. They offer different shades too stress green plants, including black lava stone. Landscape rocks work as drains for rainwater, form paths or banks and give a good replacement for mulch covering.
stone beds also have benefits over dug wood or bark cover, because no tree must be cut for it. Rocks are tougher in dryness than grass, which needs much water and mowing.
Even so there are some downsides. Stone gathers deposits from dirt and rotting matter over time, which is hard to remove. Adding plants to a landscape after putting in stone can be tricky.
Some stones warm in summer, which can hurt plants and ground. The soil does not improve with stone, so soil work is wise before you lay it. Landscape fabric is needed under stone to stop it sinking into the dirt over time.
A mix of gravel and mulch only creates dirty stone piles with many unwanted grasses. Next to a building or foundation, rock is the better pick, because it helps drainage and keeps things dry. Mulch coverings keep moisture next to structures, which is not wanted.
The use of stone mulch depends a lot on the climate. In places with a lot of rain or big trees, such beds can become a messy disaster. Weeding river stones is not a simple task.
Loose rocks must be removed from sections, the space weeded and later the rocks replaced. Loose rocks in the lawn can even be dangerous if they get hit by a mower. Wooden mulch, on the otherhand, breaks down and feeds the ground below, something that simple stone cover can not do.
