How this calculator works
Estimate mulch for rectangular landscape beds and convert the result into cubic yards and common bag counts.
Formula
Cubic feet = length × width × depth in feet. Cubic yards = cubic feet ÷ 27. Bags = cubic feet ÷ bag volume.
Cubic feet = length × width × depth in feet. Cubic yards = cubic feet ÷ 27. Bags = cubic feet ÷ bag volume.
Example
A 20 × 8 ft bed at 3 inches deep requires about 40 cubic feet, or roughly 1.5 cubic yards.
Reliability check
Take several depth readings across the bed and separate tapered or circular zones. Compare loose cubic volume with the supplier’s bag size or bulk-delivery unit, then allow for settling only when needed.
How to get a better estimate
- Refresh beds often need less depth than new beds.
- Measure separate beds and add their totals.
- Bulk yards are usually easier for larger projects.
What the result means
Mulch settles and finished depth is rarely perfectly uniform. Measure several points, choose an overage that reflects the bed condition and confirm whether the supplier sells bags or bulk cubic yards.
Reference tables
Compare bed area and finished depth with the mulch table before converting bulk volume into supplier bags.