Mulch, Soil & Gravel
Depth times area, in cubic yards, cubic metres, bags and tons — for mulch, topsoil, compost, gravel, sand and decorative stone, with delivery loads and cost.
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Yards, bags and tons at once
Ten common materials
Loads and delivery
Material
Areas to cover
Rectangles and circles. For an irregular bed, split it into rectangles or take an average length and width — bulk material is not sold precisely enough for anything finer to matter.
Depth
Order this much
—
Total area—
Volume — cubic feet—
Volume — cubic metres—
Bags at the garden centre—
Weight—
Tons — as a quarry quotes it—
Pickup loads—
Wheelbarrow trips—
Which way is cheaper?
Applied to the bulk option only.
| Buying it as | Quantity | Material | Delivery | Total |
|---|
Enter your local prices to compare.
Depth guide
| Use | Depth | Coverage per cubic yard | Notes |
|---|---|---|---|
| Mulch — new bed | 3 in | 108 sq ft | Deep enough to suppress weeds for a season. |
| Mulch — topping up | 1–2 in | 162–324 sq ft | Refresh over last year's layer; do not let the total exceed 4 in. |
| Topsoil — new lawn | 4–6 in | 54–81 sq ft | Roots need real depth; 2 in of soil over clay grows nothing. |
| Compost — amending | 1–2 in | 162–324 sq ft | Tilled into the top 6 in of existing soil. |
| Gravel path | 2–3 in | 108–162 sq ft | Over a compacted base; less than 2 in will move underfoot. |
| Gravel driveway | 4–6 in | 54–81 sq ft | In two lifts, each compacted, over a geotextile. |
| Paver base — sand | 1 in | 324 sq ft | Screeded, over 4–6 in of compacted road base. |
| Play area — wood chip | 9–12 in | 27–36 sq ft | Depth is what absorbs a fall; do not skimp. |
Instructions
How to use this calculator
Step by step
- Pick the material first. Each one sets a sensible default depth and carries its own bulk density, which is what turns your cubic yards into tons and pickup loads.
- Add an area for each bed. Rectangles take a length and a width; circles take a diameter, which is right for tree rings and round beds.
- For an irregular bed, either split it into rectangles or use its average length and average width. Bulk material is sold by the quarter yard, so precision beyond that is wasted effort.
- Set the depth, or tap one of the quick buttons. The depth guide at the bottom of the page lists what each job actually needs — this is where most orders go wrong.
- Read the order figure at the top. It is rounded up to the quarter cubic yard, which is how landscape yards load a truck.
- Use the price panel to compare bulk delivery against bagged material at your local prices. Below about two cubic yards bags often win; above it, bulk almost always does.
- Check the weight and pickup-load figures before you decide to collect it yourself. A cubic yard of topsoil is over a ton — more than a half-ton pickup should carry.
Good to know
- One cubic yard covers 324 square feet at 1 inch deep. Divide 324 by your depth in inches to get the coverage per yard — it is the only landscaping number worth memorising.
- Mulch deeper than 4 inches total does more harm than good: it holds water against stems and starves roots of air. Top up to 3 inches, do not add 3 inches every year.
- Order about 10% over on mulch and soil. Beds are never quite the shape you measured, and settling takes a visible amount off the depth within a month.
- Gravel and road base need compacting in lifts of 2 to 3 inches. Dumping 6 inches and rolling it once gives you a soft layer under a hard crust.
- Keep mulch a few inches clear of trunks and stems. Mulch volcanoes piled against a tree are the most common way people kill an expensive tree slowly.
- Wet material weighs 25 to 50 percent more than dry. If a quarry quotes by the ton after rain, you get less material for the same money — ask whether the price is by weight or volume.
The maths behind it
- Volume V = area × depth ÷ 12 Area in square feet and depth in inches gives cubic feet.
- Cubic yards yd³ = ft³ ÷ 27 The unit every landscape supplier quotes in.
- Coverage per yard 324 ÷ depth in inches Square feet one cubic yard covers.
- Circle area A = π × (diameter ÷ 2)² For tree rings and round beds.
- Weight lb = ft³ × density Mulch is about 20 lb/ft³, topsoil 76, gravel 100, road base 135.
- Tons tons = lb ÷ 2000 Quarries quote stone by the ton, not the yard.
How deep should mulch be?
Three inches on a new bed. That is deep enough to block light from weed seeds and hold moisture, and shallow enough that water and air still reach the roots. When you are topping up over last year's layer, one to two inches is plenty — the total should never exceed about four inches.
How many bags is a cubic yard?
Thirteen and a half standard 2 cubic foot bags, since a cubic yard is 27 cubic feet. That is the calculation that usually decides the bulk-versus-bags question: at $4.50 a bag, a yard of mulch in bags costs about $61 before you have carried any of it.
Will a cubic yard fit in my pickup?
By volume yes — most half-ton beds hold around two cubic yards level. By weight, often no. A yard of mulch is around 500 lb and fine; a yard of topsoil is about 2,000 lb and a yard of road base nearly 3,600 lb, both well past what a half-ton truck should carry. The loads figure on this page accounts for that.
Why does the quarry quote tons when the landscape yard quotes yards?
Because a quarry has a truck scale and a landscape yard has a bucket loader. Both are legitimate; they are just measuring different things. To convert, divide the tonnage by the material's density — gravel runs about 1.35 tons per cubic yard, road base about 1.8. This page gives you both figures so you can compare two quotes that are not in the same units.
Should I put landscape fabric down first?
Under stone, yes — it keeps the stone from sinking into the soil, which is the thing that actually ruins a gravel bed. Under mulch, generally no: mulch breaks down into soil on top of the fabric and weeds root in that layer anyway, while the fabric stops the mulch from feeding the soil beneath.
How much extra should I order?
About 10% for mulch and soil, because beds are irregular and material settles. For gravel and base under compaction, allow 20% — compacted depth is meaningfully less than loose depth, and running short in the middle of a driveway means a second delivery charge.