Formula
Bags are the order volume divided by 2 cubic feet, rounded up. A retail bag that says 2 cubic feet is the yield this page uses. Tons use the weight you picked, which does not change the bag count.
yards = cubic feet ÷ 27
order = yards × (1 + waste ÷ 100)
bags = ceil(order cubic feet ÷ 2)
tons = order yards × tons per yard
Hardwood bark is 0.40 ton/yd³, mixed bark 0.30, light cedar or pine 0.20. The 0.30 figure is the middle of a commonly cited 400–800 lb/yd³ band. It was not taken from one extension bulletin. Depth presets of 2, 3, and 4 inches are conventions, not a rule.
Worked examples
10 × 20 ft × 4 in, no waste. 66.67 ft³. 34 bags of 2 cu ft. 2.47 cubic yards.
The same bed, 10% waste, mixed bark. 73.33 ft³ to order, 37 bags, 2.72 yd³, and 0.81 tons at 0.30 ton/yd³.
A triangle 6 ft by 8 ft, 3 in deep. ½ × 6 × 8 × 0.25 = 6 ft³, which is 0.22 yd³ before waste and 3 bags.
Reference
One retail bag on this page is 2.00 cubic feet. Thirteen and a half bags fill a cubic yard.
| Mulch | ton/yd³ | lb/yd³ | Note |
|---|---|---|---|
| Hardwood bark | 0.40 | 800 | About 800 lb/yd³. A mid-to-heavy bark. The usual retail bag is 2 cu ft. |
| Mixed bark | 0.30 | 600 | Planning midpoint, 600 lb/yd³, inside the common 400–800 lb/yd³ band. |
| Light cedar or pine | 0.20 | 400 | About 400 lb/yd³. |
Questions
How many 2 cubic foot bags cover 10 by 20 feet at 4 inches?
34 bags with no waste. The volume is 66.67 cubic feet, and 66.67 ÷ 2 rounds up to 34. At 10% waste that is 37 bags, or 2.72 cubic yards of bulk.
How deep should mulch be?
Two to four inches is the usual bed. This page does not pick the depth for you. Three inches is a common preset. Keep mulch off the bark of the plant.
How heavy is a yard of mulch?
Hardwood bark is entered at 0.40 ton/yd³ (800 lb). Mixed bark at 0.30 (600 lb). Light cedar or pine at 0.20 (400 lb). Wet mulch weighs more. These are planning weights, not a weighed sample.
Sources
- Bag count: order cubic feet ÷ 2, rounded up. A cubic yard is 27 cubic feet.
- Weights: hardwood 800 lb/yd³, mixed 600 lb/yd³, light cedar or pine 400 lb/yd³. Planning figures. Not confirmed against a single extension-service table.