How to calculate mulch / gravel
Cubic yards = L (ft) × W (ft) × D (in) ÷ 12 ÷ 27
Worked example. Material needed: 0.74 cubic yards.
Example inputs — Length: 20 ft; Width: 4 ft; Depth: 3 in; Bag size: 2 cu ft. Starting values are illustrative.
From George Guju, founder of Calculyn · Educational calculator guidance, not professional advice.
How it works
Volume is length × width × depth. Depth is converted from inches to feet, and 27 cubic feet make one cubic yard — the unit bulk suppliers sell by.
Assumptions & limitations
- Results are rounded for display.
Formula and assumptions reviewed October 2026 by the Calculyn team. How we build our calculators
Frequently asked questions
How deep should mulch be?
2–3 inches is typical for garden beds. Gravel paths usually need 3–4 inches.