Mulch Calculator

Mulch Volume Formula:

Volume (cu ft) = Length (ft) × Width (ft) × Depth (in) / 12

Cubic Yards = Volume (cu ft) / 27

Where:

• Length and Width define the area to be covered, measured in feet or meters
• Depth is how thick you want the mulch layer, measured in inches
• Dividing depth by 12 converts inches to feet so all measurements use the same unit
• Dividing cubic feet by 27 converts to cubic yards, which is how bulk mulch is typically sold

Recommended mulch depth by use:

Coverage per cubic yard at various depths:

• At 2 inch depth: 162 sq ft (15.1 sq m)
• At 3 inch depth: 108 sq ft (10.0 sq m)
• At 4 inch depth: 81 sq ft (7.5 sq m)

Practical Example: A flower bed that is 20 ft long and 8 ft wide with a 3-inch mulch depth: Volume = 20 x 8 x 3 / 12 = 40 cu ft Cubic yards = 40 / 27 = 1.48 cubic yards In bags: 40 / 2 = 20 standard bags (2 cu ft each)

Bag sizes:

• Standard bag: 2 cubic feet
• Large bag: 3 cubic feet
• 1 cubic yard = 27 cubic feet = approximately 13.5 standard bags

Bulk vs. bags: Buying mulch in bulk (by the cubic yard) is usually 40-60% cheaper than bagged mulch. However, bagged mulch is easier to transport and store. For projects requiring more than 3 cubic yards, bulk delivery is almost always the better value.

Tips:

• Order 5-10% extra to account for settling, irregular edges, and areas around plants
• Do not pile mulch against tree trunks (called “volcano mulching”) — keep it 3-4 inches away from the trunk to prevent rot
• Organic mulch (wood chips, bark) breaks down over time and needs refreshing every 1-2 years
• For metric users: 1 cubic meter = 1.31 cubic yards