How much mulch do I need?
Multiply the bed's square feet by the depth in inches and divide by 12 to get cubic feet. At the usual 3 inches deep, every 100 sq ft needs 25 cubic feet of mulch: about 0.93 cubic yards, 13 bags of 2 cu ft or 9 bags of 3 cu ft. One cubic yard covers about 108 sq ft at 3 inches.
How to use the mulch calculator
- Measure each bed's length and width. For round tree rings, choose Circle and enter the diameter. For odd-shaped beds, estimate the square feet or split them into rectangles and add the results.
- Choose a depth. 2–3 inches is right for most beds; 3–4 inches for weed suppression on bare ground.
- Read off cubic yards if you're buying bulk, or the number of bags if you're buying bagged mulch.
Mulch formula
cubic feet = area (sq ft) × depth (in) ÷ 12
cubic yards = cubic feet ÷ 27
2 cu ft bags = cubic feet ÷ 2
One cubic yard of mulch covers about 162 sq ft at 2 inches deep, 108 sq ft at 3 inches, or 81 sq ft at 4 inches. It equals 13.5 bags of 2 cubic feet.
Mulch needed by bed size
| Bed area (sq ft) | Yards at 2 in | 2 cu ft bags at 2 in | Yards at 3 in | 2 cu ft bags at 3 in |
|---|---|---|---|---|
| 50 | 0.31 | 5 | 0.46 | 7 |
| 100 | 0.62 | 9 | 0.93 | 13 |
| 150 | 0.93 | 13 | 1.39 | 19 |
| 200 | 1.23 | 17 | 1.85 | 25 |
| 300 | 1.85 | 25 | 2.78 | 38 |
| 500 | 3.09 | 42 | 4.63 | 63 |
| 1000 | 6.17 | 84 | 9.26 | 125 |
How deep should mulch be?
- Refreshing existing mulch: 1 inch on top of what's there.
- Flower and shrub beds: 2–3 inches.
- New beds or weedy ground: 3–4 inches. Deeper than 4 inches can starve roots of air and water.
- Around trees: 2–4 inches, kept a few inches away from the trunk. Avoid "mulch volcanoes".
Bagged or bulk mulch?
Bulk mulch is usually much cheaper per cubic yard once you need more than 2–3 yards, but there is typically a delivery fee. Bags are easier for small beds, cars without a trailer, and spreading a little at a time.
Quick answers for common sizes
Frequently asked questions
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 mulch or 9 bags of 3 cu ft mulch.
How much area does a yard of mulch cover?
About 108 sq ft at 3 inches deep, 162 sq ft at 2 inches deep, and 324 sq ft at 1 inch deep.
How many bags of mulch do I need for 100 square feet?
At 3 inches deep, 100 sq ft needs 25 cubic feet of mulch, which is 13 bags of 2 cu ft (or 9 bags of 3 cu ft).
How do I calculate how much mulch I need?
Multiply length × width to get square feet, multiply by the depth in inches and divide by 12 for cubic feet, then divide by 27 for cubic yards or by 2 for 2 cu ft bags.
How much mulch do I need for a 10 × 20 bed?
A 10 × 20 ft bed is 200 sq ft. At 3 inches deep it needs 50 cubic feet, about 1.85 cubic yards or 25 bags of 2 cu ft.
How much mulch do I need around a tree?
A ring 6 ft across is about 28 sq ft. At 3 inches deep that takes about 7 cubic feet, or 4 bags of 2 cu ft. Keep the mulch a few inches away from the trunk.
How many yards of mulch do I need?
Divide your bed area in square feet by 108 for a 3 inch layer, or by 162 for a 2 inch layer. For example, 500 sq ft at 3 inches needs about 4.6 cubic yards.