MEASURE. ESTIMATE. BUILD.
Enter your bed area and depth to find how much mulch you need in cubic yards and 2 cubic-foot bags.
Change any measurement to update your estimate.
One cubic yard of mulch equals 13.5 bags and covers 108 ft² about 3 inches deep.
Why order extra? The headline number is the exact material your project needs. When you actually order, add about 5–10% on top — the “with 5% waste” figure in the result is a safe starting point. That margin covers what you lose to compaction, cuts around edges and corners, and ordinary spillage during handling. It is cheaper to have a little left over than to stop mid-job and wait on a second delivery.
Order about 10% over and spread 3 inches — mulch settles and decomposes, so a bed mulched to 2.5 inches in spring is bare by fall. Keep it a couple inches off trunks and stems; piling it against bark ("mulch volcanoes") rots the plant. Bulk beats bags past a single yard on both price and your back, but under half a yard the bags win once you factor a delivery fee.
The math behind the tool:
cubic yards = (area ft² × depth ft) ÷ 27
bags = cubic feet ÷ 2| Material | Density | Per cubic yard |
|---|---|---|
| Bark/wood mulch | 20 lb/ft³ (dry) | 0.27 tons |
Sources: Oregon State University Extension (soil and compost volume guidance).
One cubic yard of mulch equals 13.5 bags of 2 cubic-foot mulch, since a cubic yard is 27 cubic feet.
Multiply your bed area (ft²) by the depth in feet and divide by 27 for cubic yards. A 100 ft² bed at 3 inches deep needs about 0.93 cubic yards, or 12.5 bags.
Multiply the bed area in square feet by the depth in feet, then divide by 27. At the standard 3-inch depth, one cubic yard covers about 108 square feet. So a 200 ft² bed at 3 inches needs a little under 2 cubic yards.
A cubic yard is 27 cubic feet, so coverage depends entirely on depth: about 162 ft² at 2 inches, 108 ft² at 3 inches, and 81 ft² at 4 inches. Three inches is the usual target — deep enough to suppress weeds, shallow enough not to smother roots.
Bed area in square feet × depth in feet. Bagged mulch is sold in cubic feet, most often 2 ft³ per bag, so this is the number you want at a big-box store. Bulk mulch is sold by the cubic yard — divide your cubic feet by 27 to compare the two.
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