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Mulch Calculator

Mulch keeps moisture in the soil, suppresses weeds and finishes a garden bed. Enter the size of your beds and the depth you want, and the calculator shows the bulk volume and how many bags of your chosen size to buy.

Enter your measurements

Measurements
ft
ft
in

2–4 in (5–10 cm) is widely recommended for garden beds.

Material & assumptions

Enter your measurements and press Calculate to see quantities, a material breakdown and an optional cost estimate.

How the calculation works

  • Volume = Area × Depth
  • Cubic yards = Cubic feet ÷ 27
  • Bags = Volume ÷ Bag volume (rounded up)

Bagged mulch is usually labelled in cubic feet (often 2 or 3 ft³) or litres, while bulk mulch is sold by the cubic yard or cubic metre.

Assumptions used

  • Mulch is spread at an even depth.
  • No compaction allowance is included; fresh mulch settles slightly over time.

Example calculation

A 20 × 10 ft bed covered with 3 in of mulch, using 2 ft³ bags.

  1. 1Area: 200 ft²
  2. 2Volume: 200 × (3 ÷ 12) = 50 ft³
  3. 3Cubic yards: 50 ÷ 27 = 1.85 yd³
  4. 4Bags: 50 ÷ 2 = 25 bags

Result: Buy 25 bags or about 2 cubic yards of bulk mulch.

How to measure your project

  • Measure each bed separately and add the areas together using the known area option.
  • For round beds, area = 3.1416 × radius².
  • Subtract large areas taken up by shrubs or stepping stones if you want a tighter estimate.

Frequently asked questions

How deep should mulch be?

2–4 in (5–10 cm) is widely recommended. Thinner layers let weeds through, while very deep layers can suffocate roots. Keep mulch a few inches away from tree trunks and plant stems.

How many bags of mulch make a cubic yard?

A cubic yard is 27 ft³, so it equals 13.5 bags of 2 ft³ or 9 bags of 3 ft³.

Is bulk mulch cheaper than bags?

For larger areas, bulk mulch delivered by the yard is usually cheaper per cubic foot, though delivery fees apply. Use the cost estimator with local prices to compare.

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Results are estimates based on the measurements and assumptions you enter. Always confirm product specifications, local building codes and final quantities with your supplier or a qualified professional. See our disclaimer.