Mulch Calculator
ft
ft
in
Cubic Yards0.93
Cubic Feet25.00
Bags (2 cu ft)13
This mulch calculator estimates how much mulch you need to cover a garden bed or landscape area at a given depth. Enter the bed length and width in feet plus your target depth in inches, and it returns the volume in cubic feet and cubic yards along with an estimated bag count. It helps you order the right amount and avoid costly extra trips or leftover bags.
Formula
cubicFeet = length × width × (depth ÷ 12)
- length
- Length of the bed in feet
- width
- Width of the bed in feet
- depth
- Mulch depth in inches (divided by 12 to convert to feet)
- cubicFeet
- Volume of mulch needed in cubic feet; ÷27 gives cubic yards
How it works
- Enter the bed length and width in feet and the desired mulch depth in inches.
- The calculator multiplies length × width × (depth ÷ 12) to get cubic feet, then divides by 27 to convert to cubic yards.
- It estimates bags by dividing the cubic feet by 2 and rounding up, assuming standard 2-cubic-foot mulch bags.
Worked example
A 20 ft by 10 ft bed mulched 3 inches deep.
- Convert depth: 3 ÷ 12 = 0.25 ft.
- Volume: 20 × 10 × 0.25 = 50 cubic feet.
- Cubic yards: 50 ÷ 27 ≈ 1.85.
- Bags: 50 ÷ 2 = 25 bags.
50 cubic feet (about 1.85 cubic yards), roughly 25 standard 2-cubic-foot bags.
Frequently asked questions
- How deep should I lay mulch?
- A 2 to 3 inch layer suits most garden beds and trees, suppressing weeds while letting water through. Avoid piling mulch against stems or trunks, and refresh it as it decomposes.
- How many bags of mulch will I need?
- The calculator divides the cubic feet by 2 and rounds up, assuming common 2-cubic-foot bags. If your bags hold a different volume, divide the cubic-foot total by that bag size instead.
- When is it cheaper to buy mulch in bulk?
- Bulk mulch is sold by the cubic yard and is usually more economical once you need more than roughly 10 to 13 bags, since one cubic yard equals about 13.5 two-cubic-foot bags.
- Does this work for irregularly shaped beds?
- It assumes a rectangular area. For odd shapes, break the space into rectangles, calculate each, and add the volumes, or measure the average length and width to approximate.