Mulch & Soil Calculator

Find out how much mulch, topsoil, compost or gravel you need for a bed, border or area — and how many bags to buy. Enter the length, width and depth, how many separate areas you're filling, and a waste allowance. You'll get the volume in cubic yards or cubic meters and the bag count. Updates as you type.

How it works

volume = length × width × depth × areas × (1 + waste%)

• Volume is length × width × depth with units kept consistent (depth is converted from inches/cm).
• Cubic yards = cubic feet ÷ 27 (imperial); metric is shown directly in cubic meters.
• Waste adds your allowance (10% by default) for settling, uneven ground and spillage.
• Bags = volume ÷ bag size, rounded up. Common sizes: 2 cu ft and 3 cu ft (mulch/bark), 1 cu ft (soil); 50 L metric.

Need more than about 6–8 bags? Bulk delivery by the cubic yard (or cubic meter) is usually much cheaper per unit than bagged.

FAQ

How do I calculate how much mulch I need?

Measure the length and width of the bed to get the area, then multiply by the depth you want — keeping units consistent. In feet, divide the result by 27 to get cubic yards; in meters it is already cubic meters. A 10 × 10 ft bed at 3 inches deep needs about 0.93 cubic yards, or roughly 13 bags of 2 cu ft mulch. This calculator does the maths and the bag count for you.

How many bags of mulch are in a cubic yard?

A cubic yard is 27 cubic feet, so it equals about 13.5 bags of the common 2 cu ft size or 9 bags of 3 cu ft. Bulk by the cubic yard is almost always cheaper than bags once you need more than about 6–8 bags, so the calculator shows both the volume and the bag count to help you decide.

How deep should mulch or topsoil be?

Mulch is usually applied 2–3 inches deep (5–7.5 cm) — deep enough to suppress weeds and hold moisture without smothering roots. Topsoil for a new lawn is often 4–6 inches, and gravel paths 2–3 inches over a compacted base. Deeper layers use proportionally more material, so the volume scales directly with the depth you enter.

Should I buy mulch in bags or in bulk?

Bags are convenient for small jobs and easy to carry, but bulk delivery by the cubic yard is significantly cheaper per unit once you need more than roughly 6–8 bags. A single bed or two is fine in bags; a whole garden refresh is cheaper bulk. The calculator gives you the cubic yards so you can price both ways.

How much extra should I allow?

Add about 5–10% for settling, uneven ground and spillage — beds are rarely perfectly flat and material compacts as it settles. The waste field defaults to 10%, and the formula box shows the exact volume before waste.

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