Mulch & Soil Calculator
Free mulch and soil calculator. Find cubic yards, cubic feet, and liters for a garden bed, plus the number of 2 ft³ / 3 ft³ bags and cost.
What is a mulch and soil calculator?
A mulch calculator works out how much mulch, topsoil, or compost you need to cover a garden bed — length × width × depth — and converts the volume into cubic yards, cubic feet, liters, and the number of bags to buy.
How this calculator works
- Enter the bed length and width in feet and the depth you want in inches.
- It computes volume: length × width × (depth ÷ 12) in cubic feet.
- The volume is shown as cubic yards, cubic feet, and liters.
- Enter a price per bag to see how many 2 ft³ or 3 ft³ bags you need and what they cost.
How to use the result
- Pick your depth by job: 2–3 inches of mulch for beds, 4+ inches for new soil over poor ground.
- Compare bag count against bulk delivery — for more than a cubic yard, bulk usually wins on price.
- Buy a touch more than the number — mulch settles and a thin patch looks worse than a slight surplus.
- Check the coverage guide: a cubic yard covers about 100 ft² at 3 inches deep.
How much mulch do I need per square foot?
At a typical 3-inch depth, one cubic yard covers about 100 square feet, and one cubic foot covers about 4 square feet. The rule of thumb: square feet × depth in inches ÷ 324 = cubic yards needed. For 200 ft² at 3 inches that’s 600 ÷ 324 ≈ 1.85 yd³.
Common mistakes
- Mixing units. Depth must be in feet for the formula — 3 inches is 0.25 ft, not 3.
- Undersizing. A shallow 1-inch layer looks sparse and suppresses weeds poorly; go 2–3 inches.
- Forgetting settling. Fresh mulch compacts by roughly 10–15% in the first season.
Mulch volume math is the same length×width×depth geometry as the concrete calculator — just with yards and bags instead of yards and trucks. For raised beds, the lumber calculator prices the frame that holds the soil.