How the calculator works
Enter the bed's length and width, its diameter for a round bed, or the area if you already know it, and the depth of mulch.
- Volume: area in square feet × depth in inches ÷ 12 = cubic feet.
- Cubic yards: cubic feet ÷ 27. Bulk mulch is sold by the cubic yard.
- Bags: cubic feet ÷ the bag size, rounded up. The usual bag is 2 cubic feet; 1.5 and 3 cu ft bags are also common.
- Coverage: one cubic yard covers 324 ÷ depth square feet: 108 square feet at 3 inches.
The calculator adds nothing for settling unless you ask it to. Mulch settles a little after the first rain, which is why 3 inches at spreading time is a good target for a bed that should stay at 2 to 3 inches.
Mulch chart: cubic yards and 2 cu ft bags
| Area | 2 in deep | 3 in deep | 4 in deep |
|---|---|---|---|
| 50 sq ft | 0.31 yd³ · 5 bags | 0.46 yd³ · 7 bags | 0.62 yd³ · 9 bags |
| 100 sq ft | 0.62 yd³ · 9 bags | 0.93 yd³ · 13 bags | 1.23 yd³ · 17 bags |
| 200 sq ft | 1.23 yd³ · 17 bags | 1.85 yd³ · 25 bags | 2.47 yd³ · 34 bags |
| 500 sq ft | 3.09 yd³ · 42 bags | 4.63 yd³ · 63 bags | 6.17 yd³ · 84 bags |
| 1,000 sq ft | 6.17 yd³ · 84 bags | 9.26 yd³ · 125 bags | 12.35 yd³ · 167 bags |
How far a cubic yard goes
| Depth | Square feet per cubic yard |
|---|---|
| 1 in | 324 sq ft |
| 2 in | 162 sq ft |
| 3 in | 108 sq ft |
| 4 in | 81 sq ft |
| 6 in | 54 sq ft |
Example: three beds at 3 inches
You want 3 inches of shredded hardwood in a 4 × 20 ft bed along the house, a 6 × 12 ft bed by the fence and a round bed 8 feet across under a tree.
- Areas: 4 × 20 = 80 square feet, 6 × 12 = 72 square feet, and π × 4² = 50.3 square feet. In all, 202.3 square feet.
- Volume: 202.3 × 3 ÷ 12 = 50.6 cubic feet.
- Cubic yards: 50.6 ÷ 27 = 1.87 cubic yards. Order 2 yards in bulk.
- Bags: 50.6 ÷ 2 rounds up to 26 bags of 2 cu ft.
Enter the total of 202.3 square feet with "I know the area" to check it in the calculator.
Tips
- Weed and water first. Pull weeds and soak dry soil before you spread. Mulch keeps moisture in, but it also keeps a dry bed dry.
- Top up, do not pile on. Old mulch breaks down. Rake it loose and add an inch or so each year rather than another full 3 inches.
- Keep it off stems and trunks. Leave a few inches of bare soil around each plant.
- Measure odd beds in pieces. Split a curved bed into rectangles and circles, add the areas, then use the total.
- Compare bulk and bags. At 13.5 bags of 2 cu ft per yard, bulk delivery usually wins above 2 or 3 yards.
Frequently asked questions
How much mulch do I need for 100 square feet?
At 3 inches deep, 100 square feet takes 25 cubic feet of mulch, which is 0.93 cubic yards or 13 bags of 2 cu ft. At 2 inches it takes 0.62 cubic yards (9 bags), and at 4 inches 1.23 cubic yards (17 bags).
How many square feet does a yard of mulch cover?
One cubic yard covers 324 square feet 1 inch deep, so it covers 162 square feet at 2 inches, 108 square feet at 3 inches and 81 square feet at 4 inches.
How many bags of mulch are in a yard?
A cubic yard is 27 cubic feet, so it equals 13.5 bags of 2 cu ft, 18 bags of 1.5 cu ft or 9 bags of 3 cu ft. Bagged mulch usually costs more per yard than a bulk delivery once you need more than about 2 yards.
How deep should mulch be?
2 to 3 inches suits most garden beds and around trees and shrubs. Fine mulches such as shredded leaves or pine straw can be thinner, coarse bark or wood chips a little thicker, and 3 to 4 inches works for paths. More than 4 inches can keep water and air from the roots.
Should mulch touch the base of a tree?
No. Keep mulch a few inches away from trunks and stems. Mulch piled against a trunk, sometimes called a mulch volcano, holds moisture against the bark and invites rot, disease and rodents.
How much does a yard of mulch weigh?
Roughly 400 to 800 pounds, depending on the wood and how wet it is. A fresh, wet load of hardwood mulch weighs the most. Rubber mulch is much heavier, around 1,000 pounds or more per cubic yard.
Last updated October 20, 2026.