Mulch, Compost & Topsoil Calculator
Work out how much mulch, compost, topsoil or stone a garden needs. Get cubic yards and cubic feet, the weight of the load, bags of 1.5, 2 and 3 cu ft, and a bulk-versus-bagged cost check for one or several beds.
Written by Suhaib Hassan. Weights are typical values and change with moisture. Our methodology.
It multiplies bed area by depth, adds a settling allowance, and converts cubic feet to yards, bags and weight.
Bulk yards and bagged cubic feet are hard to compare by eye. This shows both and what each option costs.
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Buy one or two spare bags for edges and settling. Bag prices scale from your 2 cu ft price.
Depth and coverage guide
Area covered by one cubic yard or one 2 cu ft bag at common depths. One yard is 27 cubic feet.
| Application | Depth | Sq ft per yd³ | Sq ft per 2 cu ft bag | Refresh |
|---|---|---|---|---|
| Mulch top-dressing (existing beds) | 1 – 2 in | 162 – 324 | 12 – 24 | Annually |
| New landscape bed | 3 in | 108 | 8 | Every 2 – 3 years |
| Lawn topdressing with soil | ¼ – ½ in | 648 – 1,296 | 48 – 96 | Spring or fall |
| Raised vegetable bed fill | 6 – 8 in | 40 – 54 | 3 – 4 | Top up yearly |
| Garden path (stone or bark) | 3 – 4 in | 81 – 108 | 6 – 8 | As it thins |
How the volume is calculated
Area in square feet times depth in feet gives cubic feet. Divide by 27 for cubic yards.
Rectangle
ft³ = L × W × (depth ÷ 12)Circle
ft³ = π × (d ÷ 2)² × (depth ÷ 12)Order size
yd³ = ft³ × (1 + settling) ÷ 27Approximate weight per cubic yard
Wet material can weigh far more. Ask your supplier for the actual load weight before towing.
Worked examples
Illustrative jobs, each checked by hand. The first is the default setup.
30 × 6 ft bed, 2 in
10% settling allowance.
× 1.10 = 33 ft³
33 ÷ 27 = 1.22 yd³
33 ÷ 2 = 16.5 → 17 bags (2 cu ft)
10 ft round bed, 3 in
Standard 5% allowance.
× 3/12 = 19.63 ft³
× 1.05 = 20.61 ft³ = 0.76 yd³
Bulk or bags?
1.22 yd³ at $45 per yd³ against 17 bags at $4.50.
bags = 17 × 4.50 = $76.50
bulk is cheaper by $21.50
How much mulch do I need?
- Measure the bed and work out its area, or enter a known area in square feet.
- Pick a depth. Two to three inches of mulch controls weeds without smothering roots.
- Choose the material and a settling allowance, since mulch and compost compact over time.
- Buy in bulk for beds over about a cubic yard and in bags for small jobs.
Keep mulch a few inches away from tree trunks and house walls. Deep piles against bark can cause rot.
By Suhaib Hassan · Reviewed 29 September 2026 · How CalculatePilot verifies formulas →
Sources
- Colorado State University Extension, Mulches for Home Grounds, on mulch depth and placement.
- NIST Special Publication 811, for cubic foot, cubic yard and cubic metre conversion factors.
Frequently asked questions
How much does a cubic yard of mulch cover?
One cubic yard (27 cubic feet) covers about 162 square feet at 2 inches deep, 108 square feet at 3 inches, and 324 square feet at 1 inch.
How deep should mulch be?
Two to three inches is typical for flower and shrub beds. Use about one inch when refreshing existing mulch. Very deep layers can hold too much moisture against plant stems.
Is bulk or bagged mulch cheaper?
Bulk is usually cheaper per cubic foot once you need more than about a cubic yard, but you must collect it or pay for delivery. Enter your local prices above to compare the two.
Why add a settling allowance?
Fresh mulch and compost compress and break down. Adding 5% to 10% means the bed is still at the right depth after it settles.
Will a pickup truck carry a cubic yard?
Often yes for light mulch, but soil and stone are heavy. A full yard of topsoil or gravel can be well over a ton, so check your truck's payload rating.
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