How mulch coverage calculator works
Mulch is bought by volume, but gardeners think in area and depth. This calculator multiplies your bed's area by the depth you want — 2–3 inches is the usual recommendation for weed suppression, 3–4 for brand-new beds — and converts that slab of material into the units stores actually sell: cubic feet, cubic yards, cubic meters and liters.
The conversions are fixed: one cubic yard is 27 cubic feet, and one cubic foot is about 28.3 liters. A 100 sq ft bed at 3 inches deep works out to 100 × 0.25 = 25 cubic feet, which is 0.93 cubic yards — just under one yard of bulk delivery. The same job in metric: a 10 m² bed at 7.5 cm needs 0.75 m³, or 750 liters.
Give the tool a bag size and it rounds the volume up to whole bags — the standard 2 cu ft bag is preselected, and 1, 1.5 and 3 cu ft bags are common too. Past roughly one cubic yard, bulk delivery is usually cheaper per yard than bagged, and the cubic-yards figure is exactly what you quote when ordering a drop. Everything runs in your browser; no measurements are uploaded.