Free tool
Mulch calculator
Add each bed, set the depth, and get cubic yards for a bulk order, bag counts for 2 and 3 cubic foot bags, and the cost either way.
How it's calculated
- Area (sq ft) = length × width, or π × (diameter ÷ 2)² for a round bed
- Volume (cu ft) = total area × depth (in) ÷ 12
- Cubic yards = cubic feet ÷ 27
- Bags = cubic feet ÷ bag size (2 or 3 cu ft), rounded up
How to use it
- 1Measure each bed. Measure each bed as a rectangle (length × width), a circle (diameter), or enter its area in square feet.
- 2Set the depth. Enter the depth in inches. University extension guidance is 2 to 4 inches for most organic mulch.
- 3Read the volume. The calculator converts the area and depth to cubic feet and cubic yards.
- 4Compare bulk and bags. Enter your price per cubic yard and per bag to see which costs less for this job.
Worked example
Two beds: 20 ft × 6 ft and a round bed 8 ft across, mulched 3 inches deep.
- Area = 120 + π × 4² = 120 + 50.3 = 170.3 sq ft
- Volume = 170.3 × 3 ÷ 12 = 42.6 cu ft
- Cubic yards = 42.6 ÷ 27 = 1.58 cu yd
- Bags = 42.6 ÷ 2 = 22 two-cubic-foot bags, or 42.6 ÷ 3 = 15 three-cubic-foot bags
Order 1.75 cubic yards in bulk, or 22 two-cubic-foot bags.
Sources
- Iowa State University Extension and Outreach, How to Determine the Amount of Mulch Needed for a Garden Bed (Aaron Steil). Accessed 2026-11-03.
Volume = area × depth in feet; hardwood chipped or shredded mulch is typically spread 2–4 inches thick; bagged mulch comes in 2 and 3 cubic foot bags; divide cubic feet by 27 for cubic yards.
- University of Tennessee Agricultural Extension Service, SP 617: Mulching Your Trees and Landscapes (Wayne K. Clatterbuck). Accessed 2026-11-03.
Mulch should be no more than 2–4 inches deep; more than 4 inches restricts soil oxygen exchange with the roots. Don't pile mulch against trunks.
FAQ
Mulch calculator questions
Have a question we didn't cover? Book a demo and ask a product specialist.
How deep should mulch be?
Iowa State and University of Tennessee extension guidance is 2 to 4 inches for most organic mulch. More than 4 inches can restrict oxygen to roots, and mulch should be pulled back from trunks rather than piled against them.
How many bags of mulch are in a cubic yard?
A cubic yard is 27 cubic feet, so it equals 13.5 two-cubic-foot bags or 9 three-cubic-foot bags. Round up when buying.
How much area does a cubic yard of mulch cover?
At 3 inches deep, one cubic yard covers 108 sq ft (27 cu ft × 12 ÷ 3). At 2 inches it covers 162 sq ft, and at 4 inches 81 sq ft.
Should I order extra?
Fresh mulch settles and beds are rarely perfect shapes, so many contractors round up to the next quarter or half yard. The calculator shows the exact volume so you can choose how much to add.
Is bulk or bagged mulch cheaper?
For most jobs over a cubic yard or two, bulk costs less even with delivery. Enter both prices and the calculator shows the cost each way.
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