How Much Mulch Do I Need? Bags vs. Bulk Yards

Area × depth = volume

Mulch is sold by volume, so you need cubic feet: bed area in square feet times the depth in feet. One cubic yard (27 cubic feet) covers 108 sq ft at 3 inches deep, or 162 sq ft at 2 inches.

For a 200 sq ft bed at 3 inches, that's 200 × 0.25 = 50 cubic feet, or about 1.85 cubic yards.

Try it Mulch & Soil Calculator → Find cubic yards and how many bags of mulch, topsoil or gravel you need for a bed, with a rough cost.

Bags vs. bulk

Bagged mulch is usually 2 cubic feet, so it takes about 13.5 bags to equal one cubic yard. Our 50 cu ft bed is 25 bags — or under 2 yards delivered. Once you're past about 6–8 bags, bulk delivery is cheaper and far less hauling.

• 2–3 inches is the sweet spot: enough to suppress weeds and hold moisture, not so deep it smothers roots.
• Refreshing existing mulch? Measure only the top-up depth you actually need.
• Keep mulch a couple of inches back from trunks and stems.

Same math for soil and gravel

Topsoil, compost and gravel are sold the same way. Gravel is heavier — about 1.4 tons per cubic yard — so suppliers may quote it by weight; convert with the volume you calculated here.