Mulch Calculator

Work out how much mulch your beds and tree rings need, in cubic yards and in bags, and compare buying bags with bulk delivery. Your inputs stay in your browser.

Your beds and mulch

Your beds

Shape

Mulch is often spread 2 to 3 inches deep.

Bags or bulk

Common bags hold 2 or 3 cubic feet; check the label.

0.89 cu yd · 12 bags of 2 cu ft. See full results

Example: 2 beds of 12 × 4 ft, 3 inches deep, in 2 cubic foot bags. Enter your numbers to update.

Your mulch estimate

Mulch needed
0.89 cu yd
24.0 cu ft for 96 sq ft
Bags of 2 cu ft
12
Rounded up to whole bags
Coverage
108 sq ft per yard
At 3 in deep

Bags or bulk?

Add a bag price and a bulk price per cubic yard to compare the cost.

How to calculate mulch

  1. Area: length × width, or π × (diameter ÷ 2)² for a round bed. A tree ring 6 feet across is 28.3 square feet.
  2. Volume: area × depth in feet (inches ÷ 12). The example's 96 square feet at 3 inches is 24.0 cubic feet.
  3. Cubic yards = cubic feet ÷ 27 (NIST: tables of units of measurement): 0.89 cubic yards.
  4. Bags = cubic feet ÷ bag size, rounded up: 12 bags of 2 cubic feet, or 8 of 3.

Depth and coverage

One cubic yard covers 108 square feet at 3 inches and 162 at 2 inches. Topping up an existing layer usually needs less than a new bed. Keep mulch pulled back from tree trunks and plant stems.

What this calculator does not include

  • Settling: fresh mulch compacts over time, so some people add a little extra.
  • Irregular beds. Split them into rectangles and circles and add the results.
  • Delivery minimums, which vary by supplier.

Methodology and testing

Automated tests compare areas, volumes, bag counts, coverage and costs with an independent calculation, and check that an exact multiple of a bag size is not rounded up an extra bag. How we build and test calculators.

Sources

  • Gravel Calculator

    Cubic yards and tons of gravel for rectangular or round areas, with density, compaction allowance and cost.

  • Concrete Calculator

    Cubic yards and bags of concrete for slabs, footings and post holes, with a waste allowance and a bags-vs-ready-mix cost check.

  • Square Footage Calculator

    Square feet of a rectangle, circle, triangle or trapezoid in any unit, with square yards, square meters, acres and cost.

  • Cubic Yard Calculator

    Cubic yards for rectangles, circles and triangles, or the area a delivery covers, in cubic feet, cubic meters, bags and truckloads.