Mulch Calculator

How much mulch do I need?

To figure out how much mulch you need, multiply the bed’s length × width × depth (in feet) to get cubic feet, then divide by 2 for the number of standard 2 cu ft bags (or by 27 for bulk cubic yards). For example, a 20 ft × 4 ft bed at 3 inches deep needs 20 cubic feet — exactly 10 bags, or about 0.74 cubic yards in bulk. There are 13.5 bags in a cubic yard. Enter your bed above for an instant estimate you can print or share.

How we calculate mulch

• Rectangular: area (sq ft) = length × width
• Circular: area (sq ft) = π × (diameter ÷ 2)²
• Volume (cu ft) = area × depth — all in feet
• Bags = ⌈ volume (cu ft) ÷ bag size ⌉ · standard bag = 2 cu ft
• Cubic yards = cubic feet ÷ 27 · 13.5 bags = 1 cubic yard
• Coverage: 1 cu yd covers 27 ÷ depth(ft) sq ft (108 sq ft at 3 in)

How to use this calculator

1. Pick a shape. Choose a rectangular or circular bed.
2. Enter dimensions. Type length and width (or diameter) and set the depth — 3 in is the default.
3. Choose a bag size. Keep the standard 2 cu ft bag or switch to 1.5 or 3 cu ft.
4. Read your estimate. See the number of bags and the bulk cubic yards, then print or share it.

Tips & real-world notes

• Keep mulch 2–3 inches off trunks and stems — avoid “mulch volcanoes” that rot bark.
• Above about 1 cubic yard, bulk mulch is much cheaper than bags — compare the two.
• Fine or double-shredded mulch settles faster; coarse bark holds its depth longer.
• 3 inches is the sweet spot for weed suppression and moisture retention in most beds.