Mulch & Soil Calculator

Find out how much mulch, soil, compost, or gravel you need — in cubic yards, cubic feet, and bags — plus an estimate of the cost.

How to calculate mulch and soil

Mulch, soil, and gravel are sold by volume. To find how much you need:

Cubic yards = area (sq ft) × depth (ft) ÷ 27

Since depth is usually measured in inches, divide it by 12 first. This calculator handles that, then shows the volume in both cubic yards (for bulk delivery) and bags (for smaller jobs).

Recommended depths

UseRecommended depth
Refreshing existing mulch1–2 in
Standard garden beds2–3 in
New beds / weed suppression3–4 in
Topsoil for new lawns3–6 in

Tips

  • Don't overdo it. More than 3–4 inches of mulch can suffocate roots and trap moisture against stems.
  • Bulk is cheaper. If you need more than about 1 cubic yard (around 13–14 bags), bulk delivery usually wins on price.
  • Gravel is heavy. Many suppliers sell gravel by weight — confirm how many square feet a ton covers at your chosen depth.

Frequently asked questions

How much mulch do I need for a 200 sq ft bed?
At 3 inches deep, a 200 sq ft bed needs about 50 cubic feet, which is roughly 1.85 cubic yards or about 25 two-cubic-foot bags.
How many bags are in a cubic yard?
About 13–14 bags, based on the common 2 cubic foot bag size and 27 cubic feet per cubic yard.
How deep should mulch be?
2–3 inches for most beds. Don't exceed 3–4 inches, which can harm plants.
Can I use this for soil or gravel?
Yes — the volume math is identical. Just remember gravel is often sold by weight, so check coverage with your supplier.

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